CVE-2026-5430Authentication Bypass via JWT Algorithm Mismatch in Multiple WSO2 Products Allows Account Takeover

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.

10.0 CRITICALEPSS 22.39%⚡ Known Exploited (CISA KEV)NVD: Analyzed

Last updated: 2026-09-25 12:53 UTC

Overview Affected Products References

NVD CVE.org

Overview

Severity

Score	Severity	Version	Vector String
10.0	CRITICAL	3.1WSO2 (CNA)	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CISA required action

⚡ Known exploited · remediation due Sep 27, 2026

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.

Details

CVE ID: CVE-2026-5430
Status: Analyzed
Assigner (CNA): WSO2
Published: Aug 6, 2026
Last modified: 2026-09-25 12:53 UTC
Weaknesses: CWE-347 · Improper Validation of Certificate With Host Mismatch

Sources

Refreshed hourly from the sources above. Last fetched 2026-11-08 08:05 UTC.