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CVE-2026-5430

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

  • Critical 10.0
  • Exploited: added to CISA KEV 24 Sep 2026

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.

Key facts

Published
6 Aug 2026
Last changed
25 Sep 2026
Assigned by
WSO2
KEV added
24 Sep 2026
KEV fix due
27 Sep 2026
EPSS
22.39% likely to be exploited in the next 30 days, higher than 97.733% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: yes; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 10.0CVSS 3.1, Criticalfrom the CNA (WSO2)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

What to do

  • Follow the instructions given on https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5328/#solution https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5328/#solutionCNA solution statement
  • 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 KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

CAPEC-239 CAPEC-239: Token Verification Bypass (CNA impact statement)

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
WSO2WSO2 Universal Gateway
  • Default status: unaffected
  • 4.5.0 up to but excluding 4.5.0.57 (affected)
  • 4.6.0 up to but excluding 4.6.0.21 (affected)
WSO2WSO2 Traffic Manager
  • Default status: unaffected
  • 4.5.0 up to but excluding 4.5.0.56 (affected)
  • 4.6.0 up to but excluding 4.6.0.21 (affected)
WSO2WSO2 API Control Plane
  • Default status: unaffected
  • 4.5.0 up to but excluding 4.5.0.58 (affected)
  • 4.6.0 up to but excluding 4.6.0.22 (affected)
WSO2WSO2 API Manager
  • Default status: unaffected
  • 0 up to but excluding 4.1.0 (unknown)
  • 4.1.0 up to but excluding 4.1.0.257 (affected)
  • 4.2.0 up to but excluding 4.2.0.197 (affected)
  • 4.3.0 up to but excluding 4.3.0.108 (affected)
  • 4.4.0 up to but excluding 4.4.0.72 (affected)
  • 4.5.0 up to but excluding 4.5.0.57 (affected)
  • 4.6.0 up to but excluding 4.6.0.21 (affected)
WSO2WSO2 Carbon API Manager Rest API Utility
  • Default status: unknown
  • 9.20.74 up to but excluding 9.20.74.401 (affected)
  • 9.28.116 up to but excluding 9.28.116.417 (affected)
  • 9.29.120 up to but excluding 9.29.120.236 (affected)
  • 9.30.67 up to but excluding 9.30.67.167 (affected)
  • 9.31.86 up to but excluding 9.31.86.158 (affected)
  • 9.32.147 up to but excluding 9.32.147.59 (affected)
  • 9.33.106 up to and including * (unaffected)

Timeline

  1. 6 Aug 2026 Published
  2. 24 Sep 2026 CVE-2026-5430 added to CISA KEV
  3. 24 Sep 2026 Added to the CISA KEV catalogue

Weakness

References