CRITICAL Actively exploited CWE-347

CVE-2026-5430

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

WSO2·Multiple Products

10.0/ 10

CVSS 3.1

Critical severity

22%

EPSS exploit odds

Chance of exploitation in the next 30 days

Higher than 98% of all CVEs

Listed

CISA KEV catalog

Added: Sep 24, 2026
Fix due: Sep 27, 2026
Ransomware: Not known

Timeline

Published: Aug 6, 2026
Updated: Sep 25, 2026
First covered: Sep 25, 2026
Latest story: 2 months ago

Summary

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.

CWE-347Improper Validation of Certificate With Host Mismatch

Attack profile

Attack vectorNetwork

ComplexityLow

PrivilegesNone

User interactionNone

ScopeChanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

CISA required action

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.

Affected products

WSO2 Universal Gateway4.5.0 to before 4.5.0.574.6.0 to before 4.6.0.21
WSO2 Traffic Manager4.5.0 to before 4.5.0.564.6.0 to before 4.6.0.21
WSO2 API Control Plane4.5.0 to before 4.5.0.584.6.0 to before 4.6.0.22
WSO2 API Manager4.1.0 to before 4.1.0.2574.2.0 to before 4.2.0.1974.3.0 to before 4.3.0.1084.4.0 to before 4.4.0.72
WSO2 Carbon API Manager Rest API Utility9.20.74 to before 9.20.74.4019.28.116 to before 9.28.116.4179.29.120 to before 9.29.120.2369.30.67 to before 9.30.67.167

References

CVE.org recordcve.org NVD entrynvd.nist.gov CISA KEV listingcisa.gov Vendor advisorysecurity.docs.wso2.com