PYSEC-0000-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 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...