CVE-2026-114615High· 7.4▾ TwilightAuthlib is a Python library which builds OAuth and OpenID Connect servers. From 1.3.1 until 1.9.0, OctKey.import_key() checks asymmetric-key markers only at byte zero while Authlib's PEM loaders accept leading whitespace, comments, or a …
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 40.7 · likelihood 0 · exploitation 0
Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.
Authlib is a Python library which builds OAuth and OpenID Connect servers. From 1.3.1 until 1.9.0, OctKey.import_key() checks asymmetric-key markers only at byte zero while Authlib's PEM loaders accept leading whitespace, comments, or a byte-order mark. In deployments that use the documented mixed algorithm registry and already configure verification with PEM or certificate bytes containing such a prefix, an unauthenticated attacker who knows those same public-key bytes can use them as an HMAC secret and forge HS256 tokens with arbitrary identity or authorization claims. This is a bypass of the remediation for CVE-2024-37568. The module-level jwt object reaches OctKey.import_key() in authlib/jose/rfc7518/oct_key.py, where POSSIBLE_UNSAFE_KEYS fails to identify prefixed asymmetric key material. This issue is fixed in version 1.9.0.
authlib >= 1.3.1, < 1.9.0Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-114618Medium· 6.8Authlib: Default JWT bearer grant accepts assertions for the wrong audience
CVE-2026-114619Medium· 4.6Authlib: OpenID implicit grant checks raw scope instead of allowed scope before issuing ID tokens
CVE-2026-114620Medium· 5.4Authlib: Unvalidated request_uri fetch in JWT-secured authorization request (JAR) leading to SSRF
CVE-2026-114617Medium· 4.2Authlib: ID token can disable its own nonce validation via the nonce_supported claim
CVE-2026-96760Critical· 9.8Authlib (v1.7.2 and below) contains a signature verification bypass vulnerability
CVE-2026-27962Critical· 9.1Authlib is a Python library which builds OAuth and OpenID Connect servers