CVE-2026-5430criticalunder attackCWE-347

CVE-2026-5430: critical vulnerability in WSO2 API Control Plane

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

Published · Updated

78Vexday Risk Score

Prioritize patching. It under exploitation confirmed by CISA and has a public proof of concept.

ssvc Actcvss 10epss 0.6%
from disclosure to weapon41 days
Published on NVDAug 6
1st PoC+41d
CISA KEV+49d
exploitation probability
0.6%top 54% of all CVEs
observed exploitation
yesCISA + VulnCheck
3 public exploit(s)
Action required by CISAfederal deadline: 2026-09-27

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.

In short

A flaw in JWT token validation allows attackers to bypass authentication by using unsupported algorithms, gaining unauthorized access to accounts including admin accounts without needing valid credentials.

Technical detail

The JWT validation mechanism fails to restrict token algorithms to explicitly configured ones (CWE-347), allowing an attacker to craft tokens with arbitrary algorithms that bypass signature verification. This network-accessible vulnerability requires no authentication or user interaction, resulting in complete compromise of confidentiality, integrity, and availability within affected tenants.

Summary generated and translated by AI from the 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Affected products
WSO2 · WSO2 API Control PlaneWSO2 · WSO2 API ManagerWSO2 · WSO2 Carbon API Manager Rest API UtilityWSO2 · WSO2 Traffic ManagerWSO2 · WSO2 Universal Gateway
public PoCs found — 3
githubgithub.com/abraxas/CVE-2026-5430★ 1githubgithub.com/HORKimhab/CVE-2026-5430★ 0vulncheckvulncheck.com/xdb/331d5cf317afunverified
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
Related CVEs — WSO2 API Control Plane

In the same product, most dangerous first.

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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