CVE-2026-5430

What is 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.

Timeline

• 2026-08-06Published to the U.S. National Vulnerability Database (NVD)
• 2026-09-24Added to the CISA Known Exploited Vulnerabilities (KEV) catalog
• 2026-09-25First covered in a defend.network daily briefing
• 2026-09-25NVD record last updated
• 2026-09-27CISA federal remediation deadline (BOD 22-01)

CISA Known Exploited Vulnerability

WSO2 Multiple Products Path Traversal Vulnerability

Affected product

WSO2 Multiple Products

NVD also lists CPE entries for: Wso2 Api Control Plane, Wso2 Api Manager, Wso2 Traffic Manager, Wso2 Universal Gateway

References

• https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5328/
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-5430
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• https://nvd.nist.gov/vuln/detail/CVE-2026-5430

Referenced in our briefings & reports

• Vulnerability Priority Report – Week 3 of September 2026 (September 21 – 27)
• Microsoft, WSO2, Adobe vulnerabilities under active exploitation; Roundcube actively abused (2026-09-25)