CVE-2026-114616: high-severity vulnerability in authlib
Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.4epss 0.3%
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.1, Authlib's OctKey.import_key() and HMAC signing and verification path accept zero-length key material. If an application's secret lookup can return an empty string or empty bytes, a remote attacker can compute the deterministic HS256, HS384, or HS512 signature for arbitrary token claims and have Authlib treat the token as authentic. This issue is fixed in version 1.9.1.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Affected products
authlib · authlibRelated CVEs — authlib
In the same product, most dangerous first.
CVE-2025-61920HIGHAuthlib is vulnerable to Denial of Service via Oversized JOSE SegmentsEPSS 0.6%CVE-2026-27962CRITICALAuthlib JWS JWK Header Injection: Signature Verification BypassEPSS 0.6%CVE-2026-28802HIGHAuthlib: Setting `alg: none` and a blank signature appears to bypass signature verificationEPSS 0.5%CVE-2025-62706MEDIUMAuthlib : JWE zip=DEF decompression bomb enables DoSEPSS 0.5%CVE-2026-114620MEDIUMAuthlib: Unvalidated request_uri fetch in JWT-secured authorization request (JAR) leading to SSRFEPSS 0.4%CVE-2026-114618MEDIUMAuthlib: Default JWT bearer grant accepts assertions for the wrong audienceEPSS 0.4%