Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)

影響: pip:Authlib < 1.9.1 → 1.9.1

Reporter: Cavan Loughran, Celvex Group Inc. Summary Authlib's symmetric (oct) key handling accepts an empty key (empty bytes b'' / empty string '') as a valid HMAC signing and verification key. An empty HMAC key produces a deterministic digest that any party can reproduce, so an attacker who knows (or can cause) the application to verify a token with an empty key can forge arbitrary tokens that pass HS256/HS384/HS512 signature verification. This is the Authlib member of the cross-language empty…

在 GitHub Advisory Database 阅读

2026/10/28 01:09，GitHub Advisory Database 发布了“Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)”（类型：漏洞公告）。严重程度为“高危”（high）。相关技术：Python。CVE：CVE-2026-114616。