Oidc
Monthly
ID Token signature verification bypass in OIDC::Lite Perl library through version 0.12.1 allows unauthenticated remote attackers to forge authentication tokens by controlling the algorithm allowlist used during verification. When a relying party calls the verify method without pinning a specific algorithm, the library extracts the ‘alg’ value from the attacker-controlled token header and passes it as an accepted-algorithm allowlist, enabling ‘alg=none’ (no signature check) or key‑confusion attacks (e.g., RS256 to HS256). An attacker can impersonate any user by crafting a token with arbitrary ‘sub’ claims. No active exploitation has been confirmed, and the EPSS score (0.17%) suggests low immediate threat, but the issue is critical for unpatched systems using the unpinned verification path.
ID Token signature verification bypass in OIDC::Lite Perl library through version 0.12.1 allows unauthenticated remote attackers to forge authentication tokens by controlling the algorithm allowlist used during verification. When a relying party calls the verify method without pinning a specific algorithm, the library extracts the ‘alg’ value from the attacker-controlled token header and passes it as an accepted-algorithm allowlist, enabling ‘alg=none’ (no signature check) or key‑confusion attacks (e.g., RS256 to HS256). An attacker can impersonate any user by crafting a token with arbitrary ‘sub’ claims. No active exploitation has been confirmed, and the EPSS score (0.17%) suggests low immediate threat, but the issue is critical for unpatched systems using the unpinned verification path.