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Vulnerabilities / CVE-2026-5430

CVE-2026-5430

Published 2026-08-06 · published (not yet in NVD)

CVE-2026-5430

Authentication Bypass via JWT Algorithm Mismatch in Multiple WSO2 Products Allows Account Takeover

Exploited in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2026-09-24, with a fix-by date of 2026-09-27. Patch it first.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

10.0 CRITICAL
CVSS 3.1 · CNA
22%
chance of exploitation in the next 30 days (EPSS; higher than 97% of CVEs)

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.

Scores

10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HCNA

Affected products

  • WSO2 WSO2 Universal Gateway: 4.5.0 to < 4.5.0.57; 4.6.0 to < 4.6.0.21
  • WSO2 WSO2 Traffic Manager: 4.5.0 to < 4.5.0.56; 4.6.0 to < 4.6.0.21
  • WSO2 WSO2 API Control Plane: 4.5.0 to < 4.5.0.58; 4.6.0 to < 4.6.0.22
  • WSO2 WSO2 API Manager: 4.1.0 to < 4.1.0.257; 4.2.0 to < 4.2.0.197; 4.3.0 to < 4.3.0.108; 4.4.0 to < 4.4.0.72; 4.5.0 to < 4.5.0.57; 4.6.0 to < 4.6.0.21
  • WSO2 WSO2 Carbon API Manager Rest API Utility: 9.20.74 to < 9.20.74.401; 9.28.116 to < 9.28.116.417; 9.29.120 to < 9.29.120.236; 9.30.67 to < 9.30.67.167; 9.31.86 to < 9.31.86.158; 9.32.147 to < 9.32.147.59

Weakness: CWE-347

1 references (advisories, patches, write-ups)

Sources: CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.

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