CVE-2026-5430

The JWT authentication mechanism accepts tokens signed with algorithms other than those explicitly configured or supported. This allows an attacker to craft a JWT with an unsupported algorithm, which is then incorrectly validated, leading to unauthorized access. Successful exploitation of this vulnerability may result in unauthorized access to the system, including the potential compromise of administrative accounts and full account takeover. The CVSS score is adjusted to 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) in single-tenant deployments, reflecting that the impact is contained within a single security authority boundary.

CVSS
10.0
EPSS
0.004 (28.6th percentile)
CISA KEV
Added 2026-09-24, due 2026-09-27
Exploitation
active
Public exploits
1 repositories
State
PUBLISHED

Coverage

What we observed

  1. poc publishedpoc-in-github
  2. kev addedcisa-kev