CVE-2026-114616CWE-1391CWE-287CWE-326

CVE-2026-114616

High · published October 23, 2026

CVSS v3.1
7.4
EPSS
0%
Percentile
10.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.4 · HIGH
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00212 · 10.9th percentile
Weaknesses
CWE-1391 · Use of Weak Credentials; CWE-287 · Improper Authentication; CWE-326 · Inadequate Encryption Strength
Published
2026-10-23T02:18Z
References (3)
https://github.com/authlib/authlib/commit/4ff30db442c70e29486e1982cb0ad37c037f5f4b · [email protected]https://github.com/authlib/authlib/releases/tag/v1.9.1 · [email protected]https://github.com/authlib/authlib/security/advisories/GHSA-8m4g-j4wp-wgcg · [email protected]
EPSS history
Timeline
  • 24 OCT 03:52Z
    EPSS moved — → 0%
    epss
  • 22 OCT 21:14Z
    Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)
    cvelistv5
  • 22 OCT 21:14Z
    Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)
    cvelistv5