CVE-2026-41387

@@ -1,5 +1,10 @@
 import Foundation
 
+struct HostEnvOverrideDiagnostics: Equatable {
+    var blockedKeys: [String]
+    var invalidKeys: [String]
+}
+
 enum HostEnvSanitizer {
     /// Generated from src/infra/host-env-security-policy.json via scripts/generate-host-env-security-policy-swift.mjs.
     /// Parity is validated by src/infra/host-env-security.policy-parity.test.ts.
@@ -41,6 +46,67 @@ enum HostEnvSanitizer {
         return filtered.isEmpty ? nil : filtered
     }
 
+    private static func isPortableHead(_ scalar: UnicodeScalar) -> Bool {
+        let value = scalar.value
+        return value == 95 || (65...90).contains(value) || (97...122).contains(value)
+    }
+
+    private static func isPortableTail(_ scalar: UnicodeScalar) -> Bool {
+        let value = scalar.value
+        return self.isPortableHead(scalar) || (48...57).contains(value)
+    }
+
+    private static func normalizeOverrideKey(_ rawKey: String) -> String? {
+        let key = rawKey.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !key.isEmpty else { return nil }
+        guard let first = key.unicodeScalars.first, self.isPortableHead(first) else {
+            return nil
+        }
+        for scalar in key.unicodeScalars.dropFirst() {
+            if self.isPortableTail(scalar) || scalar == "(" || scalar == ")" {
+                continue
+            }
+            return nil
+        }
+        return key
+    }
+
+    private static func sortedUnique(_ values: [String]) -> [String] {
+        Array(Set(values)).sorted()
+    }
+
+    static func inspectOverrides(
+        overrides: [String: String]?,
+        blockPathOverrides: Bool = true) -> HostEnvOverrideDiagnostics
+    {
+        guard let overrides else {
+            return HostEnvOverrideDiagnostics(blockedKeys: [], invalidKeys: [])
+        }
+
+        var blocked: [String] = []
+        var invalid: [String] = []
+        for (rawKey, _) in overrides {
+            let candidate = rawKey.trimmingCharacters(in: .whitespacesAndNewlines)
+            guard let normalized = self.normalizeOverrideKey(rawKey) else {
+                invalid.append(candidate.isEmpty ? rawKey : candidate)
+                continue
+            }
+            let upper = normalized.uppercased()
+            if blockPathOverrides, upper == "PATH" {
+                blocked.append(upper)
+                continue
+            }
+            if self.isBlockedOverride(upper) || self.isBlocked(upper) {
+                blocked.append(upper)
+                continue
+            }
+        }
+
+        return HostEnvOverrideDiagnostics(
+            blockedKeys: self.sortedUnique(blocked),
+            invalidKeys: self.sortedUnique(invalid))
+    }
+
     static func sanitize(overrides: [String: String]?, shellWrapper: Bool = false) -> [String: String] {
         var merged: [String: String] = [:]
         for (rawKey, value) in ProcessInfo.processInfo.environment {
@@ -57,8 +123,7 @@ enum HostEnvSanitizer {
 
         guard let effectiveOverrides else { return merged }
         for (rawKey, value) in effectiveOverrides {
-            let key = rawKey.trimmingCharacters(in: .whitespacesAndNewlines)
-            guard !key.isEmpty else { continue }
+            guard let key = self.normalizeOverrideKey(rawKey) else { continue }
             let upper = key.uppercased()
             // PATH is part of the security boundary (command resolution + safe-bin checks). Never
             // allow request-scoped PATH overrides from agents/gateways.

@@ -63,7 +63,23 @@ enum HostEnvSecurityPolicy {
         "OPENSSL_ENGINES",
         "PYTHONSTARTUP",
         "WGETRC",
-        "CURL_HOME"
+        "CURL_HOME",
+        "CLASSPATH",
+        "CGO_CFLAGS",
+        "CGO_LDFLAGS",
+        "GOFLAGS",
+        "CORECLR_PROFILER_PATH",
+        "PHPRC",
+        "PHP_INI_SCAN_DIR",
+        "DENO_DIR",
+        "BUN_CONFIG_REGISTRY",
+        "LUA_PATH",
+        "LUA_CPATH",
+        "GEM_HOME",
+        "GEM_PATH",
+        "BUNDLE_GEMFILE",
+        "COMPOSER_HOME",
+        "XDG_CONFIG_HOME"
     ]
 
     static let blockedOverridePrefixes: [String] = [

@@ -465,6 +465,23 @@ actor MacNodeRuntime {
             ? params.sessionKey!.trimmingCharacters(in: .whitespacesAndNewlines)
             : self.mainSessionKey
         let runId = UUID().uuidString
+        let envOverrideDiagnostics = HostEnvSanitizer.inspectOverrides(
+            overrides: params.env,
+            blockPathOverrides: true)
+        if !envOverrideDiagnostics.blockedKeys.isEmpty || !envOverrideDiagnostics.invalidKeys.isEmpty {
+            var details: [String] = []
+            if !envOverrideDiagnostics.blockedKeys.isEmpty {
+                details.append("blocked override keys: \(envOverrideDiagnostics.blockedKeys.joined(separator: ", "))")
+            }
+            if !envOverrideDiagnostics.invalidKeys.isEmpty {
+                details.append(
+                    "invalid non-portable override keys: \(envOverrideDiagnostics.invalidKeys.joined(separator: ", "))")
+            }
+            return Self.errorResponse(
+                req,
+                code: .invalidRequest,
+                message: "SYSTEM_RUN_DENIED: environment override rejected (\(details.joined(separator: "; ")))")
+        }
         let evaluation = await ExecApprovalEvaluator.evaluate(
             command: command,
             rawCommand: params.rawCommand,

@@ -33,4 +33,24 @@ struct HostEnvSanitizerTests {
         let env = HostEnvSanitizer.sanitize(overrides: ["OPENCLAW_TOKEN": "secret"])
         #expect(env["OPENCLAW_TOKEN"] == "secret")
     }
+
+    @Test func `inspect overrides rejects blocked and invalid keys`() {
+        let diagnostics = HostEnvSanitizer.inspectOverrides(overrides: [
+            "CLASSPATH": "/tmp/evil-classpath",
+            "BAD-KEY": "x",
+            "ProgramFiles(x86)": "C:\\Program Files (x86)",
+        ])
+
+        #expect(diagnostics.blockedKeys == ["CLASSPATH"])
+        #expect(diagnostics.invalidKeys == ["BAD-KEY"])
+    }
+
+    @Test func `sanitize accepts Windows-style override key names`() {
+        let env = HostEnvSanitizer.sanitize(overrides: [
+            "ProgramFiles(x86)": "D:\\SDKs",
+            "CommonProgramFiles(x86)": "D:\\Common",
+        ])
+        #expect(env["ProgramFiles(x86)"] == "D:\\SDKs")
+        #expect(env["CommonProgramFiles(x86)"] == "D:\\Common")
+    }
 }

@@ -21,6 +21,32 @@ struct MacNodeRuntimeTests {
         #expect(response.ok == false)
     }
 
+    @Test func `handle invoke rejects blocked system run env override before execution`() async throws {
+        let runtime = MacNodeRuntime()
+        let params = OpenClawSystemRunParams(
+            command: ["/bin/sh", "-lc", "echo ok"],
+            env: ["CLASSPATH": "/tmp/evil-classpath"])
+        let json = try String(data: JSONEncoder().encode(params), encoding: .utf8)
+        let response = await runtime.handleInvoke(
+            BridgeInvokeRequest(id: "req-2c", command: OpenClawSystemCommand.run.rawValue, paramsJSON: json))
+        #expect(response.ok == false)
+        #expect(response.error?.message.contains("SYSTEM_RUN_DENIED: environment override rejected") == true)
+        #expect(response.error?.message.contains("CLASSPATH") == true)
+    }
+
+    @Test func `handle invoke rejects invalid system run env override key before execution`() async throws {
+        let runtime = MacNodeRuntime()
+        let params = OpenClawSystemRunParams(
+            command: ["/bin/sh", "-lc", "echo ok"],
+            env: ["BAD-KEY": "x"])
+        let json = try String(data: JSONEncoder().encode(params), encoding: .utf8)
+        let response = await runtime.handleInvoke(
+            BridgeInvokeRequest(id: "req-2d", command: OpenClawSystemCommand.run.rawValue, paramsJSON: json))
+        #expect(response.ok == false)
+        #expect(response.error?.message.contains("SYSTEM_RUN_DENIED: environment override rejected") == true)
+        #expect(response.error?.message.contains("BAD-KEY") == true)
+    }
+
     @Test func `handle invoke rejects empty system which`() async throws {
         let runtime = MacNodeRuntime()
         let params = OpenClawSystemWhichParams(bins: [])

@@ -153,6 +153,7 @@ Docs: https://docs.openclaw.ai
 - Hardening: refresh stale device pairing requests and pending metadata (#50695) Thanks @smaeljaish771 and @joshavant.
 - Gateway: harden OpenResponses file-context escaping (#50782) Thanks @YLChen-007 and @joshavant.
 - LINE: harden Express webhook parsing to verified raw body (#51202) Thanks @gladiator9797 and @joshavant.
+- Exec: harden host env override handling across gateway and node (#51207) Thanks @gladiator9797 and @joshavant.
 - xAI/models: rename the bundled Grok 4.20 catalog entries to the GA IDs and normalize saved deprecated beta IDs at runtime so existing configs and sessions keep resolving. (#50772) thanks @Jaaneek
 
 ### Fixes

@@ -130,6 +130,22 @@ describe("exec PATH login shell merge", () => {
     expect(shellPathMock).not.toHaveBeenCalled();
   });
 
+  it("fails closed when a blocked runtime override key is requested", async () => {
+    if (isWin) {
+      return;
+    }
+    const tool = createExecTool({ host: "gateway", security: "full", ask: "off" });
+
+    await expect(
+      tool.execute("call-blocked-runtime-env", {
+        command: "echo ok",
+        env: { CLASSPATH: "/tmp/evil-classpath" },
+      }),
+    ).rejects.toThrow(
+      /Security Violation: Environment variable 'CLASSPATH' is forbidden during host execution\./,
+    );
+  });
+
   it("does not apply login-shell PATH when probe rejects unregistered absolute SHELL", async () => {
     if (isWin) {
       return;

@@ -3,6 +3,7 @@ import path from "node:path";
 import type { AgentTool, AgentToolResult } from "@mariozechner/pi-agent-core";
 import { type ExecHost, loadExecApprovals, maxAsk, minSecurity } from "../infra/exec-approvals.js";
 import { resolveExecSafeBinRuntimePolicy } from "../infra/exec-safe-bin-runtime-policy.js";
+import { sanitizeHostExecEnvWithDiagnostics } from "../infra/host-env-security.js";
 import {
   getShellPathFromLoginShell,
   resolveShellEnvFallbackTimeoutMs,
@@ -25,9 +26,7 @@ import {
   renderExecHostLabel,
   resolveApprovalRunningNoticeMs,
   runExecProcess,
-  sanitizeHostBaseEnv,
   execSchema,
-  validateHostEnv,
 } from "./bash-tools.exec-runtime.js";
 import type {
   ExecElevatedDefaults,
@@ -362,24 +361,58 @@ export function createExecTool(
       }
 
       const inheritedBaseEnv = coerceEnv(process.env);
-      const baseEnv = host === "sandbox" ? inheritedBaseEnv : sanitizeHostBaseEnv(inheritedBaseEnv);
-
-      // Logic: Sandbox gets raw env. Host (gateway/node) must pass validation.
-      // We validate BEFORE merging to prevent any dangerous vars from entering the stream.
-      if (host !== "sandbox" && params.env) {
-        validateHostEnv(params.env);
+      const hostEnvResult =
+        host === "sandbox"
+          ? null
+          : sanitizeHostExecEnvWithDiagnostics({
+              baseEnv: inheritedBaseEnv,
+              overrides: params.env,
+              blockPathOverrides: true,
+            });
+      if (
+        hostEnvResult &&
+        params.env &&
+        (hostEnvResult.rejectedOverrideBlockedKeys.length > 0 ||
+          hostEnvResult.rejectedOverrideInvalidKeys.length > 0)
+      ) {
+        const blockedKeys = hostEnvResult.rejectedOverrideBlockedKeys;
+        const invalidKeys = hostEnvResult.rejectedOverrideInvalidKeys;
+        const pathBlocked = blockedKeys.includes("PATH");
+        if (pathBlocked && blockedKeys.length === 1 && invalidKeys.length === 0) {
+          throw new Error(
+            "Security Violation: Custom 'PATH' variable is forbidden during host execution.",
+          );
+        }
+        if (blockedKeys.length === 1 && invalidKeys.length === 0) {
+          throw new Error(
+            `Security Violation: Environment variable '${blockedKeys[0]}' is forbidden during host execution.`,
+          );
+        }
+        const details: string[] = [];
+        if (blockedKeys.length > 0) {
+          details.push(`blocked override keys: ${blockedKeys.join(", ")}`);
+        }
+        if (invalidKeys.length > 0) {
+          details.push(`invalid non-portable override keys: ${invalidKeys.join(", ")}`);
+        }
+        const suffix = details.join("; ");
+        if (pathBlocked) {
+          throw new Error(
+            `Security Violation: Custom 'PATH' variable is forbidden during host execution (${suffix}).`,
+          );
+        }
+        throw new Error(`Security Violation: ${suffix}.`);
       }
 
-      const mergedEnv = params.env ? { ...baseEnv, ...params.env } : baseEnv;
-
-      const env = sandbox
-        ? buildSandboxEnv({
-            defaultPath: DEFAULT_PATH,
-            paramsEnv: params.env,
-            sandboxEnv: sandbox.env,
-            containerWorkdir: containerWorkdir ?? sandbox.containerWorkdir,
-          })
-        : mergedEnv;
+      const env =
+        sandbox && host === "sandbox"
+          ? buildSandboxEnv({
+              defaultPath: DEFAULT_PATH,
+              paramsEnv: params.env,
+              sandboxEnv: sandbox.env,
+              containerWorkdir: containerWorkdir ?? sandbox.containerWorkdir,
+            })
+          : (hostEnvResult?.env ?? inheritedBaseEnv);
 
       if (!sandbox && host === "gateway" && !params.env?.PATH) {
         const shellPath = getShellPathFromLoginShell({

@@ -56,7 +56,23 @@
     "OPENSSL_ENGINES",
     "PYTHONSTARTUP",
     "WGETRC",
-    "CURL_HOME"
+    "CURL_HOME",
+    "CLASSPATH",
+    "CGO_CFLAGS",
+    "CGO_LDFLAGS",
+    "GOFLAGS",
+    "CORECLR_PROFILER_PATH",
+    "PHPRC",
+    "PHP_INI_SCAN_DIR",
+    "DENO_DIR",
+    "BUN_CONFIG_REGISTRY",
+    "LUA_PATH",
+    "LUA_CPATH",
+    "GEM_HOME",
+    "GEM_PATH",
+    "BUNDLE_GEMFILE",
+    "COMPOSER_HOME",
+    "XDG_CONFIG_HOME"
   ],
   "blockedOverridePrefixes": ["GIT_CONFIG_", "NPM_CONFIG_"],
   "blockedPrefixes": ["DYLD_", "LD_", "BASH_FUNC_"]

@@ -8,6 +8,7 @@ import {
   isDangerousHostEnvVarName,
   normalizeEnvVarKey,
   sanitizeHostExecEnv,
+  sanitizeHostExecEnvWithDiagnostics,
   sanitizeSystemRunEnvOverrides,
 } from "./host-env-security.js";
 import { OPENCLAW_CLI_ENV_VALUE } from "./openclaw-exec-env.js";
@@ -114,6 +115,10 @@ describe("sanitizeHostExecEnv", () => {
         GIT_CONFIG_GLOBAL: "/tmp/gitconfig",
         SHELLOPTS: "xtrace",
         PS4: "$(touch /tmp/pwned)",
+        CLASSPATH: "/tmp/evil-classpath",
+        GOFLAGS: "-mod=mod",
+        PHPRC: "/tmp/evil-php.ini",
+        XDG_CONFIG_HOME: "/tmp/evil-config",
         SAFE: "ok",
       },
     });
@@ -128,6 +133,10 @@ describe("sanitizeHostExecEnv", () => {
     expect(env.GIT_CONFIG_GLOBAL).toBeUndefined();
     expect(env.SHELLOPTS).toBeUndefined();
     expect(env.PS4).toBeUndefined();
+    expect(env.CLASSPATH).toBeUndefined();
+    expect(env.GOFLAGS).toBeUndefined();
+    expect(env.PHPRC).toBeUndefined();
+    expect(env.XDG_CONFIG_HOME).toBeUndefined();
     expect(env.SAFE).toBe("ok");
     expect(env.HOME).toBe("/tmp/trusted-home");
     expect(env.ZDOTDIR).toBe("/tmp/trusted-zdotdir");
@@ -183,21 +192,24 @@ describe("sanitizeHostExecEnv", () => {
     expect(env.OPENCLAW_CLI).toBe(OPENCLAW_CLI_ENV_VALUE);
   });
 
-  it("drops non-string inherited values and non-portable inherited keys", () => {
+  it("drops non-string inherited values while preserving non-portable inherited keys", () => {
     const env = sanitizeHostExecEnv({
       baseEnv: {
         PATH: "/usr/bin:/bin",
         GOOD: "1",
         // oxlint-disable-next-line typescript/no-explicit-any
         BAD_NUMBER: 1 as any,
         "NOT-PORTABLE": "x",
+        "ProgramFiles(x86)": "C:\\Program Files (x86)",
       },
     });
 
     expect(env).toEqual({
       OPENCLAW_CLI: OPENCLAW_CLI_ENV_VALUE,
       PATH: "/usr/bin:/bin",
       GOOD: "1",
+      "NOT-PORTABLE": "x",
+      "ProgramFiles(x86)": "C:\\Program Files (x86)",
     });
   });
 });
@@ -212,11 +224,58 @@ describe("isDangerousHostEnvOverrideVarName", () => {
     expect(isDangerousHostEnvOverrideVarName("git_config_global")).toBe(true);
     expect(isDangerousHostEnvOverrideVarName("GRADLE_USER_HOME")).toBe(true);
     expect(isDangerousHostEnvOverrideVarName("gradle_user_home")).toBe(true);
+    expect(isDangerousHostEnvOverrideVarName("CLASSPATH")).toBe(true);
+    expect(isDangerousHostEnvOverrideVarName("classpath")).toBe(true);
+    expect(isDangerousHostEnvOverrideVarName("GOFLAGS")).toBe(true);
+    expect(isDangerousHostEnvOverrideVarName("goflags")).toBe(true);
+    expect(isDangerousHostEnvOverrideVarName("CORECLR_PROFILER_PATH")).toBe(true);
+    expect(isDangerousHostEnvOverrideVarName("coreclr_profiler_path")).toBe(true);
+    expect(isDangerousHostEnvOverrideVarName("XDG_CONFIG_HOME")).toBe(true);
+    expect(isDangerousHostEnvOverrideVarName("xdg_config_home")).toBe(true);
     expect(isDangerousHostEnvOverrideVarName("BASH_ENV")).toBe(false);
     expect(isDangerousHostEnvOverrideVarName("FOO")).toBe(false);
   });
 });
 
+describe("sanitizeHostExecEnvWithDiagnostics", () => {
+  it("reports blocked and invalid requested overrides", () => {
+    const result = sanitizeHostExecEnvWithDiagnostics({
+      baseEnv: {
+        PATH: "/usr/bin:/bin",
+      },
+      overrides: {
+        PATH: "/tmp/evil",
+        CLASSPATH: "/tmp/evil-classpath",
+        SAFE_KEY: "ok",
+        "BAD-KEY": "bad",
+      },
+    });
+
+    expect(result.rejectedOverrideBlockedKeys).toEqual(["CLASSPATH", "PATH"]);
+    expect(result.rejectedOverrideInvalidKeys).toEqual(["BAD-KEY"]);
+    expect(result.env.SAFE_KEY).toBe("ok");
+    expect(result.env.PATH).toBe("/usr/bin:/bin");
+    expect(result.env.CLASSPATH).toBeUndefined();
+  });
+
+  it("allows Windows-style override names while still rejecting invalid keys", () => {
+    const result = sanitizeHostExecEnvWithDiagnostics({
+      baseEnv: {
+        PATH: "/usr/bin:/bin",
+        "ProgramFiles(x86)": "C:\\Program Files (x86)",
+      },
+      overrides: {
+        "ProgramFiles(x86)": "D:\\SDKs",
+        "BAD-KEY": "bad",
+      },
+    });
+
+    expect(result.rejectedOverrideBlockedKeys).toEqual([]);
+    expect(result.rejectedOverrideInvalidKeys).toEqual(["BAD-KEY"]);
+    expect(result.env["ProgramFiles(x86)"]).toBe("D:\\SDKs");
+  });
+});
+
 describe("normalizeEnvVarKey", () => {
   it("normalizes and validates keys", () => {
     expect(normalizeEnvVarKey(" OPENROUTER_API_KEY ")).toBe("OPENROUTER_API_KEY");

@@ -2,6 +2,7 @@ import HOST_ENV_SECURITY_POLICY_JSON from "./host-env-security-policy.json" with
 import { markOpenClawExecEnv } from "./openclaw-exec-env.js";
 
 const PORTABLE_ENV_VAR_KEY = /^[A-Za-z_][A-Za-z0-9_]*$/;
+const WINDOWS_COMPAT_OVERRIDE_ENV_VAR_KEY = /^[A-Za-z_][A-Za-z0-9_()]*$/;
 
 type HostEnvSecurityPolicy = {
   blockedKeys: string[];
@@ -42,6 +43,17 @@ export const HOST_SHELL_WRAPPER_ALLOWED_OVERRIDE_ENV_KEYS = new Set<string>(
   HOST_SHELL_WRAPPER_ALLOWED_OVERRIDE_ENV_KEY_VALUES,
 );
 
+export type HostExecEnvSanitizationResult = {
+  env: Record<string, string>;
+  rejectedOverrideBlockedKeys: string[];
+  rejectedOverrideInvalidKeys: string[];
+};
+
+export type HostExecEnvOverrideDiagnostics = {
+  rejectedOverrideBlockedKeys: string[];
+  rejectedOverrideInvalidKeys: string[];
+};
+
 export function normalizeEnvVarKey(
   rawKey: string,
   options?: { portable?: boolean },
@@ -56,6 +68,17 @@ export function normalizeEnvVarKey(
   return key;
 }
 
+function normalizeHostOverrideEnvVarKey(rawKey: string): string | null {
+  const key = normalizeEnvVarKey(rawKey);
+  if (!key) {
+    return null;
+  }
+  if (PORTABLE_ENV_VAR_KEY.test(key) || WINDOWS_COMPAT_OVERRIDE_ENV_VAR_KEY.test(key)) {
+    return key;
+  }
+  return null;
+}
+
 export function isDangerousHostEnvVarName(rawKey: string): boolean {
   const key = normalizeEnvVarKey(rawKey);
   if (!key) {
@@ -80,15 +103,16 @@ export function isDangerousHostEnvOverrideVarName(rawKey: string): boolean {
   return HOST_DANGEROUS_OVERRIDE_ENV_PREFIXES.some((prefix) => upper.startsWith(prefix));
 }
 
-function listNormalizedPortableEnvEntries(
+function listNormalizedEnvEntries(
   source: Record<string, string | undefined>,
+  options?: { portable?: boolean },
 ): Array<[string, string]> {
   const entries: Array<[string, string]> = [];
   for (const [rawKey, value] of Object.entries(source)) {
     if (typeof value !== "string") {
       continue;
     }
-    const key = normalizeEnvVarKey(rawKey, { portable: true });
+    const key = normalizeEnvVarKey(rawKey, options);
     if (!key) {
       continue;
     }
@@ -97,41 +121,112 @@ function listNormalizedPortableEnvEntries(
   return entries;
 }
 
-export function sanitizeHostExecEnv(params?: {
-  baseEnv?: Record<string, string | undefined>;
+function sortUnique(values: Iterable<string>): string[] {
+  return Array.from(new Set(values)).toSorted((a, b) => a.localeCompare(b));
+}
+
+function sanitizeHostEnvOverridesWithDiagnostics(params?: {
   overrides?: Record<string, string> | null;
   blockPathOverrides?: boolean;
-}): Record<string, string> {
-  const baseEnv = params?.baseEnv ?? process.env;
+}): {
+  acceptedOverrides?: Record<string, string>;
+  rejectedOverrideBlockedKeys: string[];
+  rejectedOverrideInvalidKeys: string[];
+} {
   const overrides = params?.overrides ?? undefined;
+  if (!overrides) {
+    return {
+      acceptedOverrides: undefined,
+      rejectedOverrideBlockedKeys: [],
+      rejectedOverrideInvalidKeys: [],
+    };
+  }
+
   const blockPathOverrides = params?.blockPathOverrides ?? true;
+  const acceptedOverrides: Record<string, string> = {};
+  const rejectedBlocked: string[] = [];
+  const rejectedInvalid: string[] = [];
 
-  const merged: Record<string, string> = {};
-  for (const [key, value] of listNormalizedPortableEnvEntries(baseEnv)) {
-    if (isDangerousHostEnvVarName(key)) {
+  for (const [rawKey, value] of Object.entries(overrides)) {
+    if (typeof value !== "string") {
       continue;
     }
-    merged[key] = value;
-  }
-
-  if (!overrides) {
-    return markOpenClawExecEnv(merged);
-  }
-
-  for (const [key, value] of listNormalizedPortableEnvEntries(overrides)) {
-    const upper = key.toUpperCase();
+    const normalized = normalizeHostOverrideEnvVarKey(rawKey);
+    if (!normalized) {
+      const candidate = rawKey.trim();
+      rejectedInvalid.push(candidate || rawKey);
+      continue;
+    }
+    const upper = normalized.toUpperCase();
     // PATH is part of the security boundary (command resolution + safe-bin checks). Never allow
     // request-scoped PATH overrides from agents/gateways.
     if (blockPathOverrides && upper === "PATH") {
+      rejectedBlocked.push(upper);
       continue;
     }
     if (isDangerousHostEnvVarName(upper) || isDangerousHostEnvOverrideVarName(upper)) {
+      rejectedBlocked.push(upper);
+      continue;
+    }
+    acceptedOverrides[normalized] = value;
+  }
+
+  return {
+    acceptedOverrides,
+    rejectedOverrideBlockedKeys: sortUnique(rejectedBlocked),
+    rejectedOverrideInvalidKeys: sortUnique(rejectedInvalid),
+  };
+}
+
+export function sanitizeHostExecEnvWithDiagnostics(params?: {
+  baseEnv?: Record<string, string | undefined>;
+  overrides?: Record<string, string> | null;
+  blockPathOverrides?: boolean;
+}): HostExecEnvSanitizationResult {
+  const baseEnv = params?.baseEnv ?? process.env;
+
+  const merged: Record<string, string> = {};
+  for (const [key, value] of listNormalizedEnvEntries(baseEnv)) {
+    if (isDangerousHostEnvVarName(key)) {
       continue;
     }
     merged[key] = value;
   }
 
-  return markOpenClawExecEnv(merged);
+  const overrideResult = sanitizeHostEnvOverridesWithDiagnostics({
+    overrides: params?.overrides ?? undefined,
+    blockPathOverrides: params?.blockPathOverrides ?? true,
+  });
+  if (overrideResult.acceptedOverrides) {
+    for (const [key, value] of Object.entries(overrideResult.acceptedOverrides)) {
+      merged[key] = value;
+    }
+  }
+
+  return {
+    env: markOpenClawExecEnv(merged),
+    rejectedOverrideBlockedKeys: overrideResult.rejectedOverrideBlockedKeys,
+    rejectedOverrideInvalidKeys: overrideResult.rejectedOverrideInvalidKeys,
+  };
+}
+
+export function inspectHostExecEnvOverrides(params?: {
+  overrides?: Record<string, string> | null;
+  blockPathOverrides?: boolean;
+}): HostExecEnvOverrideDiagnostics {
+  const result = sanitizeHostEnvOverridesWithDiagnostics(params);
+  return {
+    rejectedOverrideBlockedKeys: result.rejectedOverrideBlockedKeys,
+    rejectedOverrideInvalidKeys: result.rejectedOverrideInvalidKeys,
+  };
+}
+
+export function sanitizeHostExecEnv(params?: {
+  baseEnv?: Record<string, string | undefined>;
+  overrides?: Record<string, string> | null;
+  blockPathOverrides?: boolean;
+}): Record<string, string> {
+  return sanitizeHostExecEnvWithDiagnostics(params).env;
 }
 
 export function sanitizeSystemRunEnvOverrides(params?: {
@@ -146,7 +241,7 @@ export function sanitizeSystemRunEnvOverrides(params?: {
     return overrides;
   }
   const filtered: Record<string, string> = {};
-  for (const [key, value] of listNormalizedPortableEnvEntries(overrides)) {
+  for (const [key, value] of listNormalizedEnvEntries(overrides, { portable: true })) {
     if (!HOST_SHELL_WRAPPER_ALLOWED_OVERRIDE_ENV_KEYS.has(key.toUpperCase())) {
       continue;
     }

@@ -51,6 +51,13 @@ describe("node-host sanitizeEnv", () => {
       expect(env.BASH_ENV).toBeUndefined();
     });
   });
+
+  it("preserves inherited non-portable Windows-style env keys", () => {
+    withEnv({ "ProgramFiles(x86)": "C:\\Program Files (x86)" }, () => {
+      const env = sanitizeEnv(undefined);
+      expect(env["ProgramFiles(x86)"]).toBe("C:\\Program Files (x86)");
+    });
+  });
 });
 
 describe("node-host output decoding", () => {

@@ -336,6 +336,7 @@ describe("handleSystemRunInvoke mac app exec host routing", () => {
     preferMacAppExecHost: boolean;
     runViaResponse?: ExecHostResponse | null;
     command?: string[];
+    env?: Record<string, string>;
     rawCommand?: string | null;
     systemRunPlan?: SystemRunApprovalPlan | null;
     cwd?: string;
@@ -391,6 +392,7 @@ describe("handleSystemRunInvoke mac app exec host routing", () => {
       client: {} as never,
       params: {
         command: params.command ?? ["echo", "ok"],
+        env: params.env,
         rawCommand: params.rawCommand,
         systemRunPlan: params.systemRunPlan,
         cwd: params.cwd,
@@ -1106,6 +1108,65 @@ describe("handleSystemRunInvoke mac app exec host routing", () => {
     expectApprovalRequiredDenied({ sendNodeEvent, sendInvokeResult });
   });
 
+  it("rejects blocked environment overrides before execution", async () => {
+    const { runCommand, sendInvokeResult } = await runSystemInvoke({
+      preferMacAppExecHost: false,
+      security: "full",
+      ask: "off",
+      env: { CLASSPATH: "/tmp/evil-classpath" },
+    });
+
+    expect(runCommand).not.toHaveBeenCalled();
+    expectInvokeErrorMessage(sendInvokeResult, {
+      message: "SYSTEM_RUN_DENIED: environment override rejected",
+    });
+    expectInvokeErrorMessage(sendInvokeResult, {
+      message: "CLASSPATH",
+    });
+  });
+
+  it("rejects blocked environment overrides for shell-wrapper commands", async () => {
+    const shellCommand =
+      process.platform === "win32"
+        ? ["cmd.exe", "/d", "/s", "/c", "echo ok"]
+        : ["/bin/sh", "-lc", "echo ok"];
+    const { runCommand, sendInvokeResult } = await runSystemInvoke({
+      preferMacAppExecHost: false,
+      security: "full",
+      ask: "off",
+      command: shellCommand,
+      env: {
+        CLASSPATH: "/tmp/evil-classpath",
+        LANG: "C",
+      },
+    });
+
+    expect(runCommand).not.toHaveBeenCalled();
+    expectInvokeErrorMessage(sendInvokeResult, {
+      message: "SYSTEM_RUN_DENIED: environment override rejected",
+    });
+    expectInvokeErrorMessage(sendInvokeResult, {
+      message: "CLASSPATH",
+    });
+  });
+
+  it("rejects invalid non-portable environment override keys before execution", async () => {
+    const { runCommand, sendInvokeResult } = await runSystemInvoke({
+      preferMacAppExecHost: false,
+      security: "full",
+      ask: "off",
+      env: { "BAD-KEY": "x" },
+    });
+
+    expect(runCommand).not.toHaveBeenCalled();
+    expectInvokeErrorMessage(sendInvokeResult, {
+      message: "SYSTEM_RUN_DENIED: environment override rejected",
+    });
+    expectInvokeErrorMessage(sendInvokeResult, {
+      message: "BAD-KEY",
+    });
+  });
+
   async function expectNestedEnvShellDenied(params: {
     depth: number;
     markerName: string;

@@ -14,7 +14,10 @@ import {
 } from "../infra/exec-approvals.js";
 import type { ExecHostRequest, ExecHostResponse, ExecHostRunResult } from "../infra/exec-host.js";
 import { resolveExecSafeBinRuntimePolicy } from "../infra/exec-safe-bin-runtime-policy.js";
-import { sanitizeSystemRunEnvOverrides } from "../infra/host-env-security.js";
+import {
+  inspectHostExecEnvOverrides,
+  sanitizeSystemRunEnvOverrides,
+} from "../infra/host-env-security.js";
 import { normalizeSystemRunApprovalPlan } from "../infra/system-run-approval-binding.js";
 import { resolveSystemRunCommandRequest } from "../infra/system-run-command.js";
 import { logWarn } from "../logger.js";
@@ -244,6 +247,34 @@ async function parseSystemRunPhase(
   const sessionKey = opts.params.sessionKey?.trim() || "node";
   const runId = opts.params.runId?.trim() || crypto.randomUUID();
   const suppressNotifyOnExit = opts.params.suppressNotifyOnExit === true;
+  const envOverrideDiagnostics = inspectHostExecEnvOverrides({
+    overrides: opts.params.env ?? undefined,
+    blockPathOverrides: true,
+  });
+  if (
+    envOverrideDiagnostics.rejectedOverrideBlockedKeys.length > 0 ||
+    envOverrideDiagnostics.rejectedOverrideInvalidKeys.length > 0
+  ) {
+    const details: string[] = [];
+    if (envOverrideDiagnostics.rejectedOverrideBlockedKeys.length > 0) {
+      details.push(
+        `blocked override keys: ${envOverrideDiagnostics.rejectedOverrideBlockedKeys.join(", ")}`,
+      );
+    }
+    if (envOverrideDiagnostics.rejectedOverrideInvalidKeys.length > 0) {
+      details.push(
+        `invalid non-portable override keys: ${envOverrideDiagnostics.rejectedOverrideInvalidKeys.join(", ")}`,
+      );
+    }
+    await opts.sendInvokeResult({
+      ok: false,
+      error: {
+        code: "INVALID_REQUEST",
+        message: `SYSTEM_RUN_DENIED: environment override rejected (${details.join("; ")})`,
+      },
+    });
+    return null;
+  }
   const envOverrides = sanitizeSystemRunEnvOverrides({
     overrides: opts.params.env ?? undefined,
     shellWrapper: shellPayload !== null,