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...

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...

Spring Security has Potential Security Misconfiguration when Using withIssuerLocation

Vulnerability in Spring Spring Security. When an application configures JWT decoding with NimbusJwtDecoder or NimbusReactiveJwtDecoder, it must configure an OAuth2TokenValidator separately, for example by calling setJwtValidator. This issue affects Spring Security: from 6.3.0 through 6.3.14, from...

EUVD-2026-24610

Vulnerability in Spring Spring Security. When an application configures JWT decoding with NimbusJwtDecoder or NimbusReactiveJwtDecoder, it must configure an OAuth2TokenValidator separately, for example by calling setJwtValidator.This issue affects Spring Security: from 6.3.0 through 6.3.14, from...

CVE-2026-22748 Potential Security Misconfiguration when Using withIssuerLocation

Vulnerability in Spring Spring Security. When an application configures JWT decoding with NimbusJwtDecoder or NimbusReactiveJwtDecoder, it must configure an OAuth2TokenValidator separately, for example by calling setJwtValidator.This issue affects Spring Security: from 6.3.0 through 6.3.14, from...