Actively exploited · Published Aug 6, 2026 · Assigned by WSO2
CVE-2026-5430Authentication Bypass via JWT Algorithm Mismatch in Multiple WSO2 Products Allows Account Takeover
Critical 10.0 Exploited
In plain English
A critical-severity security flaw in WSO2 API Control Plane from WSO2. Attackers are actively exploiting it in the wild (listed by CISA on September 24, 2026). The chance it is exploited in the next 30 days is estimated at 22.4% (higher than 98% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. 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.
CISA guidance
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.
Federal agencies must remediate by Sep 27, 2026.
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| WSO2 | WSO2 Universal Gateway | 4.5.0 – before 4.5.0.574.6.0 – before 4.6.0.21 |
| WSO2 | WSO2 Traffic Manager | 4.5.0 – before 4.5.0.564.6.0 – before 4.6.0.21 |
| WSO2 | WSO2 API Control Plane | 4.5.0 – before 4.5.0.584.6.0 – before 4.6.0.22 |
| WSO2 | WSO2 API Manager | 4.1.0 – before 4.1.0.2574.2.0 – before 4.2.0.1974.3.0 – before 4.3.0.1084.4.0 – before 4.4.0.724.5.0 – before 4.5.0.574.6.0 – before 4.6.0.21 |
| WSO2 | WSO2 Carbon API Manager Rest API Utility | 9.20.74 – before 9.20.74.4019.28.116 – before 9.28.116.4179.29.120 – before 9.29.120.2369.30.67 – before 9.30.67.1679.31.86 – before 9.31.86.1589.32.147 – before 9.32.147.59 |
Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H