Denial Of Service (DoS)

Authlib is vulnerable to Denial-Of-Service via Oversized JWS/JWT. The vulnerability is due to Authlib accepting base64url-encoded header or signature inputs of unbounded size, allowing attackers to send tokens with huge encoded header/signature fields that exhaust CPU and memory during verificati...

CVE-2025-61920 Authlib is vulnerable to Denial of Service via Oversized JOSE Segments

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib’s JOSE implementation accepts unbounded JWS/JWT header and signature segments. A remote attacker can craft a token whose base64url‑encoded header or signature spans hundreds of megabytes...