CVE-2026-28802

CRITICAL

Authlib 1.6.5-1.6.6 - Improper Verification of Cryptographic Signature

Title source: llm
STIX 2.1

Description

Authlib is a Python library which builds OAuth and OpenID Connect servers. From version 1.6.5 to before version 1.6.7, previous tests involving passing a malicious JWT containing alg: none and an empty signature was passing the signature verification step without any changes to the application code when a failure was expected.. This issue has been patched in version 1.6.7.

References (3)

Core 3

Scores

CVSS v3 9.8
EPSS 0.0034
EPSS Percentile 25.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-347
Status published
Products (2)
authlib/authlib 1.6.5 - 1.6.7
pypi/authlib 1.6.5 - 1.6.7PyPI
Published Mar 06, 2026
Tracked Since Mar 06, 2026