CVE-2025-68113

@@ -254,6 +254,7 @@ def self.create_challenge(options)
 
     salt = options.salt || random_bytes(salt_length).unpack1('H*')
     salt += "?#{URI.encode_www_form(params)}" unless params.empty?
+    salt += salt.end_with?('&') ? '' : '&'
 
     number = options.number || random_int(max_number)
 

@@ -87,6 +87,25 @@
       expect(Altcha.verify_solution(payload, hmac_key, true)).to be true
     end
 
+    it 'fails to verify an incorrect solution with salt splicing' do
+      challenge_options_with_expires = Altcha::ChallengeOptions.new(
+        algorithm: algorithm,
+        expires: Time.now.to_i + 3600,
+        hmac_key: hmac_key,
+        salt: salt,
+        number: 123
+      ) 
+      challenge = Altcha.create_challenge(challenge_options_with_expires)
+      payload = {
+        algorithm: algorithm,
+        challenge: challenge.challenge,
+        number: 23,
+        salt: challenge.salt + '1',
+        signature: challenge.signature
+      }
+      expect(Altcha.verify_solution(payload, hmac_key, true)).to be false
+    end
+
     it 'fails to verify an incorrect solution' do
       payload = { algorithm: algorithm, challenge: 'wrong_challenge', number: number, salt: salt, signature: 'wrong_signature' }
       expect(Altcha.verify_solution(payload, hmac_key, false)).to be false
@@ -131,7 +150,7 @@
   describe '.solve_challenge' do
     it 'solves a challenge correctly' do
       challenge = Altcha.create_challenge(challenge_options)
-      solution = Altcha.solve_challenge(challenge.challenge, salt, algorithm, 10_000, 0)
+      solution = Altcha.solve_challenge(challenge.challenge, challenge.salt, algorithm, 10_000, 0)
       expect(solution).not_to be_nil
       expect(solution.number).to eq(number)
     end

@@ -449,6 +449,7 @@ defmodule Altcha do
     params =
       if expires do
         time = if is_binary(expires), do: expires, else: Integer.to_string(expires)
+
         Map.put(
           params,
           "expires",
@@ -467,6 +468,14 @@ defmodule Altcha do
         salt
       end
 
+    # Add a delimiter to prevent parameter splicing
+    salt =
+      if String.ends_with?(salt, "&") do
+        salt
+      else
+        salt <> "&"
+      end
+
     number = number || random_int(max_number)
 
     challenge_str = "#{salt}#{number}"

@@ -223,6 +223,30 @@ defmodule AltchaTest do
 
       refute Altcha.verify_solution(invalid_payload, @valid_hmac_key)
     end
+
+    test "returns false for invalid payload with salt splicing" do
+      challenge_options = %ChallengeOptions{
+        algorithm: :sha256,
+        number: 123,
+        salt_length: 16,
+        hmac_key: @valid_hmac_key
+      }
+
+      challenge = Altcha.create_challenge(challenge_options)
+
+      payload =
+        %Payload{
+          algorithm: challenge.algorithm,
+          challenge: challenge.challenge,
+          number: 23,
+          salt: challenge.salt <> "1",
+          signature: challenge.signature
+        }
+        |> Payload.to_json()
+        |> Base.encode64()
+
+      refute Altcha.verify_solution(payload, @valid_hmac_key)
+    end
   end
 
   describe "verify_server_signature/2" do
@@ -231,13 +255,14 @@ defmodule AltchaTest do
         %ServerSignaturePayload{
           algorithm: "SHA-256",
           verification_data: "verified=true",
-          signature: Altcha.hmac_hex(Altcha.hash("verified=true", :sha256), :sha256, @valid_hmac_key),
+          signature:
+            Altcha.hmac_hex(Altcha.hash("verified=true", :sha256), :sha256, @valid_hmac_key),
           verified: true
         }
         |> ServerSignaturePayload.to_json()
         |> Base.encode64()
 
-      assert { true, _ } = Altcha.verify_server_signature(payload, @valid_hmac_key)
+      assert {true, _} = Altcha.verify_server_signature(payload, @valid_hmac_key)
     end
 
     test "returns false for invalid server signature" do
@@ -251,7 +276,7 @@ defmodule AltchaTest do
         |> Jason.encode!()
         |> Base.encode64()
 
-      assert { false, _ } = Altcha.verify_server_signature(invalid_payload, @valid_hmac_key)
+      assert {false, _} = Altcha.verify_server_signature(invalid_payload, @valid_hmac_key)
     end
   end
 

@@ -376,6 +376,11 @@ public static Challenge createChallenge(ChallengeOptions options) throws Excepti
             salt += "?" + encodeParams(params);
         }
 
+        // Add a delimiter to prevent parameter splicing
+        if (!salt.endsWith("&")) {
+            salt += "&";
+        }
+
         long number = options.number != null ? options.number
                 : (options.secureRandomNumber ? randomIntSecure(maxNumber) : randomInt(maxNumber));
         String challengeStr = hashHex(algorithm, salt + number);

@@ -74,6 +74,25 @@ public void testVerifySolution() throws Exception {
         assertTrue(isValid);
     }
 
+    @Test
+    public void testVerifySolutionSaltSplicing() throws Exception {
+        Altcha.ChallengeOptions options = new Altcha.ChallengeOptions();
+        options.number = 123L;
+        options.hmacKey = "secret";
+
+        Altcha.Challenge challenge = Altcha.createChallenge(options);
+
+        Altcha.Payload payload = new Altcha.Payload();
+        payload.algorithm = challenge.algorithm;
+        payload.challenge = challenge.challenge;
+        payload.number = 23L;
+        payload.salt = challenge.salt + "1";
+        payload.signature = challenge.signature;
+
+        boolean isValid = Altcha.verifySolution(payload, options.hmacKey, false);
+        assertFalse(isValid);
+    }
+
     @Test
     public void testExtractParams() throws Exception {
         Map<String, String> params = Altcha.extractParams("testSalt?param1=value1&param2=value2");

@@ -386,6 +386,11 @@ func CreateChallenge(options ChallengeOptions) (Challenge, error) {
 		salt = salt + "?" + params.Encode()
 	}
 
+	// Add a delimiter to prevent parameter splicing
+	if !strings.HasSuffix(salt, "&") {
+		salt += "&"
+	}
+
 	var number int64
 	if options.Number == nil {
 		randomNumber, err := randomInt(maxNumber)

@@ -253,6 +253,40 @@ func TestVerifySolutionSafe(t *testing.T) {
 	}
 }
 
+func TestVerifySolutionSaltSplicing(t *testing.T) {
+	expires := time.Now().Add(10 * time.Minute)
+	var num int64 = 123
+	options := ChallengeOptions{
+		HMACKey:    "test-key",
+		SaltLength: 16,
+		Algorithm:  SHA256,
+		Expires:    &expires,
+		Number:     &num,
+		Params:     url.Values{"foo": {"bar"}},
+	}
+
+	challenge, err := CreateChallenge(options)
+	if err != nil {
+		t.Fatalf("CreateChallenge() error = %v", err)
+	}
+
+	payload := Payload{
+		Algorithm: challenge.Algorithm,
+		Challenge: challenge.Challenge,
+		Number:    23,
+		Salt:      challenge.Salt + "1",
+		Signature: challenge.Signature,
+	}
+
+	valid, err := VerifySolution(payload, "test-key", true)
+	if err != nil {
+		t.Fatalf("VerifySolution() error = %v", err)
+	}
+	if valid {
+		t.Error("VerifySolution() should return false for invalid spliced solution")
+	}
+}
+
 func TestExtractParams(t *testing.T) {
 	payload := Payload{
 		Salt: "abc123?foo=bar&baz=qux",

@@ -154,7 +154,7 @@ public function verifySolution(string|array $data, bool $checkExpires = true): b
      */
     private function extractParams(Payload $payload): array
     {
-        $saltParts = explode('?', rtrim($payload->salt, ';'));
+        $saltParts = explode('?', $payload->salt);
         if (\count($saltParts) > 1) {
             parse_str($saltParts[1], $params);
 

@@ -39,8 +39,8 @@ public function __construct(
         }
 
         // Add a delimiter to prevent parameter splicing
-        if (!str_ends_with($salt, ';')) {
-            $salt .= ';';
+        if (!str_ends_with($salt, '&')) {
+            $salt .= '&';
         }
 
         $this->salt = $salt;

@@ -31,8 +31,8 @@ async function createChallenge(options) {
         salt = salt + '?' + params.toString();
     }
     // Add a delimiter to prevent parameter splicing
-    if (!salt.endsWith(';')) {
-        salt = salt + ';';
+    if (!salt.endsWith('&')) {
+        salt = salt + '&';
     }
     const number = options.number === undefined ? (0, helpers_js_1.randomInt)(maxnumber) : options.number;
     const challenge = await (0, helpers_js_1.hashHex)(algorithm, salt + number);
@@ -54,7 +54,7 @@ function extractParams(payload) {
     if (typeof payload === 'string') {
         payload = JSON.parse(atob(payload));
     }
-    return Object.fromEntries(new URLSearchParams(payload?.salt?.split('?')?.[1]?.replace(/;$/, '') || ''));
+    return Object.fromEntries(new URLSearchParams(payload?.salt?.split('?')?.[1] || ''));
 }
 /**
  * Verifies the solution provided by the client.

@@ -43,8 +43,8 @@ export async function createChallenge(
     salt = salt + '?' + params.toString();
   }
   // Add a delimiter to prevent parameter splicing
-  if (!salt.endsWith(';')) {
-    salt = salt + ';';
+  if (!salt.endsWith('&')) {
+    salt = salt + '&';
   }
   const number =
     options.number === undefined ? randomInt(maxnumber) : options.number;
@@ -69,7 +69,7 @@ export function extractParams(payload: string | Payload | Challenge) {
     payload = JSON.parse(atob(payload)) as Payload;
   }
   return Object.fromEntries(
-    new URLSearchParams(payload?.salt?.split('?')?.[1]?.replace(/;$/, '') || '')
+    new URLSearchParams(payload?.salt?.split('?')?.[1] || '')
   );
 }
 

@@ -22,8 +22,8 @@ export async function createChallenge(options) {
         salt = salt + '?' + params.toString();
     }
     // Add a delimiter to prevent parameter splicing
-    if (!salt.endsWith(';')) {
-        salt = salt + ';';
+    if (!salt.endsWith('&')) {
+        salt = salt + '&';
     }
     const number = options.number === undefined ? randomInt(maxnumber) : options.number;
     const challenge = await hashHex(algorithm, salt + number);
@@ -45,7 +45,7 @@ export function extractParams(payload) {
     if (typeof payload === 'string') {
         payload = JSON.parse(atob(payload));
     }
-    return Object.fromEntries(new URLSearchParams(payload?.salt?.split('?')?.[1]?.replace(/;$/, '') || ''));
+    return Object.fromEntries(new URLSearchParams(payload?.salt?.split('?')?.[1] || ''));
 }
 /**
  * Verifies the solution provided by the client.

@@ -43,8 +43,8 @@ export async function createChallenge(
     salt = salt + '?' + params.toString();
   }
   // Add a delimiter to prevent parameter splicing
-  if (!salt.endsWith(';')) {
-    salt = salt + ';';
+  if (!salt.endsWith('&')) {
+    salt = salt + '&';
   }
   const number =
     options.number === undefined ? randomInt(maxnumber) : options.number;
@@ -69,7 +69,7 @@ export function extractParams(payload: string | Payload | Challenge) {
     payload = JSON.parse(atob(payload)) as Payload;
   }
   return Object.fromEntries(
-    new URLSearchParams(payload?.salt?.split('?')?.[1]?.replace(/;$/, '') || '')
+    new URLSearchParams(payload?.salt?.split('?')?.[1] || '')
   );
 }
 

@@ -106,7 +106,7 @@ describe('challenge', () => {
         signature: expect.any(String),
       } satisfies Challenge);
       expect(challenge.salt.length).toBeGreaterThan(25);
-      expect(challenge.salt.endsWith('?abc=123&xyz=000;')).toBeTruthy();
+      expect(challenge.salt.endsWith('?abc=123&xyz=000&')).toBeTruthy();
       expect(challenge.challenge.length).toEqual(64);
       expect(challenge.signature.length).toEqual(64);
     });