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.

  • Published Aug 6, 2026
  • CVSS 10.0 critical
  • 0.6% chance of exploitation in the next 30 days (EPSS)
  • In CISA's Known Exploited Vulnerabilities catalog

Affected software

In the news

CVE-2026-5430 at the National Vulnerability Database