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.

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Fri, 23 Oct 2026 03:45:00 +0000

Type Values Removed Values Added
First Time appeared Authlib
Authlib authlib
Vendors & Products Authlib
Authlib authlib

Fri, 23 Oct 2026 00:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)
Weaknesses CWE-1391
CWE-287
CWE-326
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-22T21:14:03.060Z

Reserved: 2026-10-21T20:34:25.600Z

Link: CVE-2026-114616

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-22T22:18:04.420

Modified: 2026-10-22T22:18:04.420

Link: CVE-2026-114616

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T03:30:15Z

Weaknesses