CVE-2026-5430
Received Received - Intake

JWT Algorithm Confusion Leading to Unauthorized Access

Publication date: 2026-08-06

Last updated on: 2026-08-06

Assigner: WSO2 LLC

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.

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Meta Information

Published
2026-08-06
Last Modified
2026-08-06
Generated
2026-08-06
AI Q&A
2026-08-06
EPSS Evaluated
N/A
NVD
CVE-2026-5430
EUVD
EUVD-2026-53822

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
wso2 api_control_plane From 4.5.0 (inc) to 4.6.0 (inc)
wso2 api_manager From 4.1.0 (inc) to 4.6.0 (inc)
wso2 traffic_manager From 4.5.0 (inc) to 4.6.0 (inc)
wso2 universal_gateway From 4.5.0 (inc) to 4.6.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-347 The product does not verify, or incorrectly verifies, the cryptographic signature for data.

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Executive Summary

This vulnerability involves the JWT authentication system accepting tokens signed with unsupported algorithms. Attackers can exploit this by creating a JWT with an invalid algorithm, which the system incorrectly validates, allowing unauthorized access to the system.

Impact Analysis

Exploitation may lead to unauthorized system access, including compromise of administrative accounts and full account takeover. The impact is severe, with a CVSS score of 9.8, indicating high confidentiality, integrity, and availability impacts.

Mitigation Strategies

Configure the JWT authentication mechanism to explicitly reject tokens signed with unsupported algorithms. Ensure only trusted algorithms are allowed and validate token signatures strictly.

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