CVE-2026-33939

@@ -1,6 +1,7 @@
 import parser from './parser';
 import WhitespaceControl from './whitespace-control';
 import * as Helpers from './helpers';
+import Exception from '../exception';
 import { extend } from '../utils';
 
 export { parser };
@@ -11,6 +12,9 @@ extend(yy, Helpers);
 export function parseWithoutProcessing(input, options) {
   // Just return if an already-compiled AST was passed in.
   if (input.type === 'Program') {
+    // When a pre-parsed AST is passed in, validate all node values to prevent
+    // code injection via type-confused literals.
+    validateInputAst(input);
     return input;
   }
 
@@ -32,3 +36,66 @@ export function parse(input, options) {
 
   return strip.accept(ast);
 }
+
+function validateInputAst(ast) {
+  validateAstNode(ast);
+}
+
+function validateAstNode(node) {
+  if (node == null) {
+    return;
+  }
+
+  if (Array.isArray(node)) {
+    node.forEach(validateAstNode);
+    return;
+  }
+
+  if (typeof node !== 'object') {
+    return;
+  }
+
+  if (node.type === 'PathExpression') {
+    if (!isValidDepth(node.depth)) {
+      throw new Exception(
+        'Invalid AST: PathExpression.depth must be an integer'
+      );
+    }
+    if (!Array.isArray(node.parts)) {
+      throw new Exception('Invalid AST: PathExpression.parts must be an array');
+    }
+    for (let i = 0; i < node.parts.length; i++) {
+      if (typeof node.parts[i] !== 'string') {
+        throw new Exception(
+          'Invalid AST: PathExpression.parts must only contain strings'
+        );
+      }
+    }
+  } else if (node.type === 'NumberLiteral') {
+    if (typeof node.value !== 'number' || !isFinite(node.value)) {
+      throw new Exception('Invalid AST: NumberLiteral.value must be a number');
+    }
+  } else if (node.type === 'BooleanLiteral') {
+    if (typeof node.value !== 'boolean') {
+      throw new Exception(
+        'Invalid AST: BooleanLiteral.value must be a boolean'
+      );
+    }
+  }
+
+  Object.keys(node).forEach(propertyName => {
+    if (propertyName === 'loc') {
+      return;
+    }
+    validateAstNode(node[propertyName]);
+  });
+}
+
+function isValidDepth(depth) {
+  return (
+    typeof depth === 'number' &&
+    isFinite(depth) &&
+    Math.floor(depth) === depth &&
+    depth >= 0
+  );
+}

@@ -686,9 +686,18 @@ JavaScriptCompiler.prototype = {
     let foundDecorator = this.nameLookup('decorators', name, 'decorator'),
       options = this.setupHelperArgs(name, paramSize);
 
+    // Store the resolved decorator in a variable and verify it is a function before
+    // calling it. Without this, unregistered decorators can cause an unhandled TypeError
+    // (calling undefined), which crashes the process — enabling Denial of Service.
+    this.decorators.push(['var decorator = ', foundDecorator, ';']);
+    this.decorators.push([
+      'if (typeof decorator !== "function") { throw new Error(',
+      this.quotedString('Missing decorator: "' + name + '"'),
+      '); }'
+    ]);
     this.decorators.push([
       'fn = ',
-      this.decorators.functionCall(foundDecorator, '', [
+      this.decorators.functionCall('decorator', '', [
         'fn',
         'props',
         'container',

@@ -16,6 +16,7 @@ export function createProtoAccessControl(runtimeOptions) {
   methodWhiteList['__defineGetter__'] = false;
   methodWhiteList['__defineSetter__'] = false;
   methodWhiteList['__lookupGetter__'] = false;
+  methodWhiteList['__lookupSetter__'] = false;
   extend(methodWhiteList, runtimeOptions.allowedProtoMethods);
 
   return {

@@ -138,7 +138,7 @@ export function template(templateSpec, env) {
       for (let i = 0; i < len; i++) {
         let result = depths[i] && container.lookupProperty(depths[i], name);
         if (result != null) {
-          return depths[i][name];
+          return result;
         }
       }
     },
@@ -349,21 +349,21 @@ export function wrapProgram(
 export function resolvePartial(partial, context, options) {
   if (!partial) {
     if (options.name === '@partial-block') {
-      partial = options.data['partial-block'];
+      partial = lookupOwnProperty(options.data, 'partial-block');
     } else {
-      partial = options.partials[options.name];
+      partial = lookupOwnProperty(options.partials, options.name);
     }
   } else if (!partial.call && !options.name) {
     // This is a dynamic partial that returned a string
     options.name = partial;
-    partial = options.partials[partial];
+    partial = lookupOwnProperty(options.partials, partial);
   }
   return partial;
 }
 
 export function invokePartial(partial, context, options) {
   // Use the current closure context to save the partial-block if this partial
-  const currentPartialBlock = options.data && options.data['partial-block'];
+  const currentPartialBlock = lookupOwnProperty(options.data, 'partial-block');
   options.partial = true;
   if (options.ids) {
     options.data.contextPath = options.ids[0] || options.data.contextPath;
@@ -404,6 +404,12 @@ export function noop() {
   return '';
 }
 
+function lookupOwnProperty(obj, name) {
+  if (obj && Object.prototype.hasOwnProperty.call(obj, name)) {
+    return obj[name];
+  }
+}
+
 function initData(context, data) {
   if (!data || !('root' in data)) {
     data = data ? createFrame(data) : {};

@@ -196,16 +196,24 @@ module.exports.cli = function(opts) {
 
   const objectName = opts.partial ? 'Handlebars.partials' : 'templates';
 
+  if (opts.namespace && !isValidNamespace(opts.namespace)) {
+    throw new Handlebars.Exception('Invalid namespace format');
+  }
+
   let output = new SourceNode();
   if (!opts.simple) {
     if (opts.amd) {
+      const runtimeModulePath =
+        (opts.handlebarPath || '') + 'handlebars.runtime';
       output.add(
-        "define(['" +
-          opts.handlebarPath +
-          'handlebars.runtime\'], function(Handlebars) {\n  Handlebars = Handlebars["default"];'
+        'define([' +
+          quoteForJavaScript(runtimeModulePath) +
+          '], function(Handlebars) {\n  Handlebars = Handlebars["default"];'
       );
     } else if (opts.commonjs) {
-      output.add('var Handlebars = require("' + opts.commonjs + '");');
+      output.add(
+        'var Handlebars = require(' + quoteForJavaScript(opts.commonjs) + ');'
+      );
     } else {
       output.add('(function() {\n');
     }
@@ -255,9 +263,9 @@ module.exports.cli = function(opts) {
       }
       output.add([
         objectName,
-        "['",
-        template.name,
-        "'] = template(",
+        '[',
+        quoteForJavaScript(template.name),
+        '] = template(',
         precompiled,
         ');\n'
       ]);
@@ -277,7 +285,9 @@ module.exports.cli = function(opts) {
   }
 
   if (opts.map) {
-    output.add('\n//# sourceMappingURL=' + opts.map + '\n');
+    output.add(
+      '\n//# sourceMappingURL=' + sanitizeSourceMapComment(opts.map) + '\n'
+    );
   }
 
   output = output.toStringWithSourceMap();
@@ -307,6 +317,33 @@ function arrayCast(value) {
   return value;
 }
 
+/*
+ * Safely quotes a value for embedding in generated JavaScript strings
+ *
+ * Uses JSON.stringify which handles all special characters.
+ */
+function quoteForJavaScript(value) {
+  return JSON.stringify(String(value));
+}
+
+/**
+ * Validates that a namespace is a legitimate dotted JavaScript identifier
+ * (e.g. "App.templates") to prevent arbitrary code injection
+ */
+function isValidNamespace(namespace) {
+  return /^[A-Za-z_$][A-Za-z0-9_$]*(\.[A-Za-z_$][A-Za-z0-9_$]*)*$/.test(
+    namespace
+  );
+}
+
+/**
+ * Strips line terminators from source map URLs to prevent injection of new
+ * JavaScript lines via the sourceMappingURL comment
+ */
+function sanitizeSourceMapComment(value) {
+  return String(value).replace(/[\r\n\u2028\u2029]/g, '');
+}
+
 /**
  * Run uglify to minify the compiled template, if uglify exists in the dependencies.
  *

@@ -128,6 +128,146 @@ describe('compiler', function() {
       );
     });
 
+    it('should reject AST with invalid PathExpression depth', function() {
+      shouldThrow(
+        function() {
+          Handlebars.compile({
+            type: 'Program',
+            body: [
+              {
+                type: 'MustacheStatement',
+                escaped: true,
+                strip: { open: false, close: false },
+                path: {
+                  type: 'PathExpression',
+                  data: false,
+                  depth: '0',
+                  parts: ['this'],
+                  original: 'this'
+                },
+                params: []
+              }
+            ]
+          })();
+        },
+        Error,
+        'Invalid AST: PathExpression.depth must be an integer'
+      );
+    });
+
+    it('should reject AST with non-array PathExpression parts', function() {
+      shouldThrow(
+        function() {
+          Handlebars.compile({
+            type: 'Program',
+            body: [
+              {
+                type: 'MustacheStatement',
+                escaped: true,
+                strip: { open: false, close: false },
+                path: {
+                  type: 'PathExpression',
+                  data: false,
+                  depth: 0,
+                  parts: 'this',
+                  original: 'this'
+                },
+                params: []
+              }
+            ]
+          })();
+        },
+        Error,
+        'Invalid AST: PathExpression.parts must be an array'
+      );
+    });
+
+    it('should reject AST with non-string PathExpression part', function() {
+      shouldThrow(
+        function() {
+          Handlebars.compile({
+            type: 'Program',
+            body: [
+              {
+                type: 'MustacheStatement',
+                escaped: true,
+                strip: { open: false, close: false },
+                path: {
+                  type: 'PathExpression',
+                  data: false,
+                  depth: 0,
+                  parts: [1],
+                  original: 'this'
+                },
+                params: []
+              }
+            ]
+          })();
+        },
+        Error,
+        'Invalid AST: PathExpression.parts must only contain strings'
+      );
+    });
+
+    it('should reject AST with invalid BooleanLiteral value type', function() {
+      shouldThrow(
+        function() {
+          Handlebars.compile({
+            type: 'Program',
+            body: [
+              {
+                type: 'MustacheStatement',
+                escaped: true,
+                strip: { open: false, close: false },
+                path: {
+                  type: 'PathExpression',
+                  data: false,
+                  depth: 0,
+                  parts: ['if'],
+                  original: 'if'
+                },
+                params: [
+                  {
+                    type: 'BooleanLiteral',
+                    value: 'true',
+                    original: true
+                  }
+                ]
+              }
+            ]
+          })();
+        },
+        Error,
+        'Invalid AST: BooleanLiteral.value must be a boolean'
+      );
+    });
+
+    it('should ignore loc metadata while validating AST nodes', function() {
+      equal(
+        Handlebars.compile({
+          type: 'Program',
+          meta: null,
+          loc: { source: 'fake', start: { line: 1, column: 0 } },
+          body: [{ type: 'ContentStatement', value: 'Hello' }]
+        })(),
+        'Hello'
+      );
+    });
+
+    it('should accept AST with valid NumberLiteral values', function() {
+      equal(
+        Handlebars.compile(Handlebars.parse('{{lookup this 1}}'))(['a', 'b']),
+        'b'
+      );
+    });
+
+    it('should accept AST with valid BooleanLiteral values', function() {
+      equal(
+        Handlebars.compile(Handlebars.parse('{{#if true}}ok{{/if}}'))({}),
+        'ok'
+      );
+    });
+
     it('can pass through an empty string', function() {
       equal(Handlebars.compile('')(), '');
     });

@@ -1,6 +1,6 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
     Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-  return templates['bom'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+  return templates["bom"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
       return "a";
   },"useData":true});
   });
\ No newline at end of file

@@ -1,6 +1,6 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
   Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-return templates['empty'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+return templates["empty"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
     return "";
 },"useData":true});
 });

@@ -1,6 +1,6 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
   Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = CustomNamespace.templates = CustomNamespace.templates || {};
-return templates['empty'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+return templates["empty"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
     return "";
 },"useData":true});
 });

@@ -1,6 +1,6 @@
 (function() {
   var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-templates['empty'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+templates["empty"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
     return "";
 },"useData":true});
 })();
\ No newline at end of file

@@ -1,9 +1,9 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
   Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-templates['firstTemplate'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+templates["firstTemplate"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
     return "<div>1</div>";
 },"useData":true});
-templates['secondTemplate'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+templates["secondTemplate"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
     return "<div>2</div>";
 },"useData":true});
 return templates;

@@ -1,6 +1,6 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
   Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-return templates['artifacts/partial.template'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+return templates["artifacts/partial.template"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
     return "<div>Test Partial</div>";
 },"useData":true});
 });
\ No newline at end of file

@@ -1,6 +1,6 @@
-define(['some-path/handlebars.runtime'], function(Handlebars) {
+define(["some-path/handlebars.runtime"], function(Handlebars) {
     Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-  return templates['empty'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+  return templates["empty"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
       return "";
   },"useData":true});
   });
\ No newline at end of file

@@ -1,9 +1,9 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
     Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = someNameSpace = someNameSpace || {};
-  templates['empty'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+  templates["empty"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
       return "";
   },"useData":true});
-  templates['empty'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+  templates["empty"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
       return "";
   },"useData":true});
   return templates;

@@ -1,6 +1,6 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
     Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-  return templates['non.default.extension'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+  return templates["non.default.extension"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
       return "<div>This is a test</div>";
   },"useData":true});
   });
\ No newline at end of file

@@ -1,6 +1,6 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
 Handlebars = Handlebars["default"]; var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-return templates['known.helpers'] = template({"0":function(container,depth0,helpers,partials,data) {
+return templates["known.helpers"] = template({"0":function(container,depth0,helpers,partials,data) {
 var stack1, lookupProperty = container.lookupProperty || function(parent, propertyName) {
 if (Object.prototype.hasOwnProperty.call(parent, propertyName)) {
 return parent[propertyName];

@@ -1,6 +1,6 @@
-define(['handlebars.runtime'], function(Handlebars) {
+define(["handlebars.runtime"], function(Handlebars) {
     Handlebars = Handlebars["default"];  var template = Handlebars.template, templates = Handlebars.templates = Handlebars.templates || {};
-  return Handlebars.partials['partial.template'] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
+  return Handlebars.partials["partial.template"] = template({"compiler":[8,">= 4.3.0"],"main":function(container,depth0,helpers,partials,data) {
       return "<div>Test Partial</div>";
   },"useData":true});
   });
\ No newline at end of file

@@ -182,7 +182,7 @@ describe('precompiler', function() {
       return 'amd';
     };
     Precompiler.cli({ templates: [emptyTemplate], amd: true, partial: true });
-    equal(/return Handlebars\.partials\['empty'\]/.test(log), true);
+    equal(/return Handlebars\.partials\["empty"\]/.test(log), true);
     equal(/template\(amd\)/.test(log), true);
   });
   it('should output multiple amd partials', function() {
@@ -405,4 +405,85 @@ describe('precompiler', function() {
       });
     });
   });
+
+  describe('GHSA-xjpj-3mr7-gcpf: precompiler output escaping', function() {
+    var FullHandlebars = require('../dist/cjs/handlebars')['default'];
+
+    function runCliAndCaptureOutput(options) {
+      var output = '';
+      var oldLog = console.log;
+      console.log = function() {
+        output += Array.prototype.join.call(arguments, '');
+      };
+
+      try {
+        Precompiler.cli(options);
+      } finally {
+        console.log = oldLog;
+      }
+
+      return output;
+    }
+
+    it('should not inject raw template names into generated code', function() {
+      var output = runCliAndCaptureOutput({
+        templates: [
+          {
+            name: "evil'];global.__xjpjName=1;//",
+            source: ''
+          }
+        ],
+        amd: true
+      });
+
+      expect(output).to.not.match(/\['evil'\];global\.__xjpjName=1/);
+    });
+
+    it('should not inject raw commonjs option values into generated code', function() {
+      var output = runCliAndCaptureOutput({
+        templates: [{ name: 'safe', source: '' }],
+        commonjs: 'handlebars");global.__xjpjCommon=1;//'
+      });
+
+      expect(output).to.not.match(
+        /require\("handlebars"\);global\.__xjpjCommon=1/
+      );
+    });
+
+    it('should reject invalid namespace expressions', function() {
+      expect(function() {
+        runCliAndCaptureOutput({
+          templates: [{ name: 'safe', source: '' }],
+          namespace: 'App.ns;global.__xjpjNamespace=1;//'
+        });
+      }).to.throw(/Invalid namespace/);
+    });
+
+    it('should sanitize sourceMappingURL comment values', function() {
+      var oldPrecompile = FullHandlebars.precompile;
+      var oldWriteFileSync = fs.writeFileSync;
+      FullHandlebars.precompile = function() {
+        return {
+          code: '""',
+          map: '{"version":3,"sources":[],"names":[],"mappings":""}'
+        };
+      };
+      fs.writeFileSync = function() {};
+
+      var output;
+      try {
+        output = runCliAndCaptureOutput({
+          templates: [{ name: 'safe', source: '' }],
+          map: 'good.js.map\n;global.__xjpjMap=1;//'
+        });
+      } finally {
+        FullHandlebars.precompile = oldPrecompile;
+        fs.writeFileSync = oldWriteFileSync;
+      }
+
+      expect(output).to.not.match(
+        /sourceMappingURL=[^\n]*\n;global\.__xjpjMap=1/
+      );
+    });
+  });
 });

@@ -54,6 +54,13 @@ describe('runtime', function() {
         /Template was precompiled with an older version of Handlebars than the current runtime/
       );
     });
+
+    it('should safely resolve missing partial map entries', function() {
+      equal(
+        Handlebars.VM.resolvePartial(undefined, {}, { name: 'missing' }),
+        undefined
+      );
+    });
   });
 
   describe('#child', function() {

@@ -133,11 +133,13 @@ describe('security issues', function() {
       '{{__defineGetter__}}',
       '{{__defineSetter__}}',
       '{{__lookupGetter__}}',
+      '{{__lookupSetter__}}',
       '{{__proto__}}',
       '{{lookup this "constructor"}}',
       '{{lookup this "__defineGetter__"}}',
       '{{lookup this "__defineSetter__"}}',
       '{{lookup this "__lookupGetter__"}}',
+      '{{lookup this "__lookupSetter__"}}',
       '{{lookup this "__proto__"}}'
     ];
 
@@ -422,6 +424,159 @@ describe('security issues', function() {
         .toCompileTo('c');
     });
   });
+
+  describe('GHSA-2qvq-rjwj-gvw9: partial resolution must not use polluted prototypes', function() {
+    if (!Handlebars.compile) {
+      return;
+    }
+
+    afterEach(function() {
+      delete Object.prototype.widget;
+    });
+
+    it('should not resolve partial names from Object.prototype', function() {
+      // eslint-disable-next-line no-extend-native
+      Object.prototype.widget = '<img src=x onerror="alert(1)">';
+
+      expect(function() {
+        Handlebars.compile('<div>{{> widget}}</div>')({});
+      }).to.throw(/could not be found/);
+    });
+  });
+
+  describe('GHSA-2w6w-674q-4c4q, GHSA-xhpv-hc6g-r9c6, GHSA-3mfm-83xf-c92r: untrusted AST inputs', function() {
+    if (!Handlebars.compile) {
+      return;
+    }
+
+    function createInjectedProgram() {
+      return {
+        type: 'Program',
+        body: [
+          {
+            type: 'MustacheStatement',
+            escaped: true,
+            strip: {
+              open: false,
+              close: false
+            },
+            path: {
+              type: 'PathExpression',
+              data: false,
+              depth: 0,
+              parts: ['lookup'],
+              original: 'lookup'
+            },
+            params: [
+              {
+                type: 'PathExpression',
+                data: false,
+                depth: 0,
+                parts: [],
+                original: 'this'
+              },
+              {
+                type: 'NumberLiteral',
+                value: '{},{})) + (Function) + (({}',
+                original: 1
+              }
+            ]
+          }
+        ]
+      };
+    }
+
+    it('should reject AST NumberLiteral type confusion in compile()', function() {
+      expect(function() {
+        var template = Handlebars.compile(createInjectedProgram());
+        template({});
+      }).to.throw(/Invalid AST/);
+    });
+
+    it('should reject AST objects passed via dynamic partial lookup', function() {
+      expect(function() {
+        var template = Handlebars.compile('{{> (lookup . "payload")}}');
+        template({
+          payload: createInjectedProgram()
+        });
+      }).to.throw(/Invalid AST|could not be found/);
+    });
+  });
+
+  describe('GHSA-442j-39wm-28r2: lookup must return checked value', function() {
+    it('should use the validated value from lookupProperty() in compat mode', function() {
+      var input = { child: {} };
+      var readCount = 0;
+      Object.defineProperty(input, 'unstable', {
+        enumerable: true,
+        get: function() {
+          readCount++;
+          return readCount === 1 ? 'first-read' : 'second-read';
+        }
+      });
+
+      expectTemplate('{{#with child}}{{unstable}}{{/with}}')
+        .withInput(input)
+        .withCompileOptions({ compat: true })
+        .toCompileTo('first-read');
+    });
+  });
+
+  describe('GHSA-9cx6-37pm-9jff: malformed decorators should fail safely', function() {
+    if (!Handlebars.compile) {
+      return;
+    }
+
+    it('should throw a controlled error for unknown decorators', function() {
+      var template = Handlebars.compile('{{*notRegistered}}');
+      expect(function() {
+        template({});
+      }).to.throw(/Missing decorator|not registered/);
+    });
+  });
+
+  describe('GHSA-new: @partial-block must not resolve from polluted prototype', function() {
+    if (!Handlebars.compile) {
+      return;
+    }
+
+    afterEach(function() {
+      delete Object.prototype['partial-block'];
+    });
+
+    it('should not resolve @partial-block from Object.prototype', function() {
+      // eslint-disable-next-line no-extend-native
+      Object.prototype['partial-block'] = '<img src=x onerror="alert(1)">';
+
+      expect(function() {
+        Handlebars.compile('{{> @partial-block}}')({});
+      }).to.throw(/could not be found/);
+    });
+
+    it('should not resolve @partial-block from Object.prototype inside a partial', function() {
+      // eslint-disable-next-line no-extend-native
+      Object.prototype['partial-block'] = '<img src=x onerror="alert(1)">';
+
+      Handlebars.registerPartial('testPartial', '{{> @partial-block}}');
+      try {
+        expect(function() {
+          Handlebars.compile('{{> testPartial}}')({});
+        }).to.throw(/could not be found/);
+      } finally {
+        Handlebars.unregisterPartial('testPartial');
+      }
+    });
+
+    it('should still render legitimate @partial-block content', function() {
+      Handlebars.registerPartial('wrapper', '<div>{{> @partial-block}}</div>');
+      try {
+        var result = Handlebars.compile('{{#> wrapper}}hello{{/wrapper}}')({});
+        expect(result).to.equal('<div>hello</div>');
+      } finally {
+        Handlebars.unregisterPartial('wrapper');
+      }
+    });
+  });
 });
 
 function wrapToAdjustContainer(precompiledTemplateFunction) {