Duplicate Advisory: Authentication bypass via jwt algorithm confusion

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-j97h-3f8r-mrjr. This link is maintained to preserve external references. Original Description A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows a...

CVE-2026-11800

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to...

CVE-2026-11800

CVE-2026-11800 concerns Keycloak services and describes a JWT algorithm confusion vulnerability in the JWT Authorization Grant flow. The issue allows an attacker with valid client credentials to bypass signature verification by forging an assertion, enabling creation of unauthorized access tokens...

CVE-2026-11800 Org.keycloak:keycloak-services: keycloak: authentication bypass via jwt algorithm confusion

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to...

CVE-2026-11800

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to...

CVE-2026-11800

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to...

org.keycloak:keycloak-services: Keycloak: Authentication bypass via JWT algorithm confusion

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to...

CVE-2026-11800: Improper Verification of Cryptographic Signature

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to...

CVE-2026-39999

CVE-2026-39999 is an authentication bypass in Apache APISIX caused by misconfigurations in the jwt-auth plugin. Affected versions are 2.2 through 3.16.0; the issue allows bypassing authentication via spoofed tokens. The entry is resolved by upgrading to v3.17.0, which fixes the vulnerability. Rel...

CVE-2026-39999 Apache APISIX: JWT Algorithm Confusion allows authentication bypass

Authentication Bypass by Spoofing vulnerability in Apache APISIX. The attacker can completely bypass authentication capitalising on certain configurations of jwt-auth plugin. This issue affects Apache APISIX: from v2.2 through v3.16.0. Users are recommended to upgrade to version v3.17.0, which...

PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed

!NOTE Exploitation requires a verifier configured with both symmetric and asymmetric algorithms in algorithms=… and a raw-JSON JWK as the key= argument, both contrary to documented usage, hence the High attack-complexity rating. Summary When the verifier is decoding JSON Web Tokens, while...

GHSA-XGMM-8J9V-C9WX PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed

!NOTE Exploitation requires a verifier configured with both symmetric and asymmetric algorithms in algorithms=… and a raw-JSON JWK as the key= argument, both contrary to documented usage, hence the High attack-complexity rating. Summary When the verifier is decoding JSON Web Tokens, while...

JWSVerifier uses algorithm from unprotected header, enabling algorithm confusion attacks

Summary JWSVerifier::getAlgorithm in src/Library/Signature/JWSVerifier.php line 144 merges protected and unprotected headers using PHP's spread operator: php $completeHeader = ...$signature-getProtectedHeader, ...$signature-getHeader; In PHP, when spreading arrays with duplicate string keys, the...

JWSVerifier uses algorithm from unprotected header, enabling algorithm confusion attacks

Summary JWSVerifier::getAlgorithm in src/Library/Signature/JWSVerifier.php line 144 merges protected and unprotected headers using PHP's spread operator: php $completeHeader = ...$signature-getProtectedHeader, ...$signature-getHeader; In PHP, when spreading arrays with duplicate string keys, the...

AZL-93033 CVE-2026-48526 affecting package python-jwt for versions less than 2.13.0-1

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, when the verifier is decoding JSON Web Tokens, while supporting both asymmetric and HMAC algorithms, the library does not validate use of JSON Web Keys in HMAC algorithm, allowing attacker to use the issuer public key as the...

jwt-pwn

jwt-pwn A zero-dependency Python 3 toolkit for discovering an...

SUSE CVE-2026-44699

LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid...

UBUNTU-CVE-2026-44699

LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid...

CVE-2026-44699

LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid...

CVE-2026-44699

LibJWT (C JSON Web Token library) versions 3.0.0–3.3.2 are vulnerable when an RSA JWK without an alg parameter is used as the verification key for HS256/HS384/HS512. In the OpenSSL backend, this can cause HMAC verification to run with a zero-length key, enabling an attacker to forge a valid JWT w...