PyJWT: Algorithm allow-list bypass when decoding with `PyJWK` / `PyJWKClient` keys

!NOTE Scored assuming a deployment where algorithm policy functions as an authentication/authorization boundary. In deployments where the algorithm policy enforces crypto agility only, the practical confidentiality impact is lower and the issue is closer to an integrity-of-policy-enforcement bug...

GHSA-JQ35-7PRP-9V3F PyJWT: Algorithm allow-list bypass when decoding with `PyJWK` / `PyJWKClient` keys

!NOTE Scored assuming a deployment where algorithm policy functions as an authentication/authorization boundary. In deployments where the algorithm policy enforces crypto agility only, the practical confidentiality impact is lower and the issue is closer to an integrity-of-policy-enforcement bug...

Linux Distros Unpatched Vulnerability : CVE-2026-48523

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode or...

Improper Verification of Cryptographic Signature

Overview Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature via the jwt.decode or jwt.decodecomplete functions when used with a PyJWK key. An attacker can bypass algorithm restrictions and gain unauthorized access to protected resources by signing...

PYSEC-2026-176

PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode or jwt.decodecomplete are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature...

CVE-2026-48523

PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode or jwt.decodecomplete are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature...

UBUNTU-CVE-2026-48523

PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode or jwt.decodecomplete are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature...

CVE-2026-48523 PyJWT: Algorithm allow-list bypass when decoding with `PyJWK` / `PyJWKClient` keys

PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode or jwt.decodecomplete are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature...

CVE-2026-48523

PyJWT vulnerability affecting versions 2.9.0–2.12.1 where verifier-side algorithm allow-list bypass occurs when decoding with a PyJWK/PyJWKClient key. The token header’s alg is checked against the caller-supplied allow-list, but the signature is verified using the algorithm bound to the PyJWK obj...