CVE-2026-97791
Received Received - Intake

SAML Token Validation Bypass in Apache CXF

Publication date: 2026-10-09

Last updated on: 2026-10-09

Assigner: Apache Software Foundation

Description
In Apache CXF, STSTokenValidator checks whether a SAML assertion is signed by a trusted certificate before deciding to send it to the STS. That result was stored in one object shared by all requests, so one request could read another's result. A remote, unauthenticated attacker could send a forged assertion signed with an untrusted certificate while legitimate requests were being processed, and it could be accepted as trusted without ever reaching the STS. Only services that use STSTokenValidator to validate SAML tokens without alwaysValidateToSts set are affected.  Users are recommended to upgrade to versions 4.2.4 or 4.1.9 or 3.6.13, which fix this issue.

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Meta Information

Published
2026-10-09
Last Modified
2026-10-09
Generated
2026-10-09
AI Q&A
2026-10-09
EPSS Evaluated
N/A
NVD
CVE-2026-97791
EUVD
EUVD-2026-95700

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
Apache Software Foundation Apache CXF 4.2.0
Apache Software Foundation Apache CXF 4.0.0
Apache Software Foundation Apache CXF 0

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in Apache CXF involves a shared object in STSTokenValidator that stores validation results for SAML assertions. A remote attacker can send a forged assertion signed with an untrusted certificate during legitimate requests. The forged assertion may be accepted as trusted without proper validation by the Security Token Service (STS). Only services using STSTokenValidator without alwaysValidateToSts set are affected.

Impact Analysis

An attacker could exploit this to bypass authentication by having their forged SAML assertion accepted as valid. This could allow unauthorized access to protected resources or data. The impact depends on the service configuration but may lead to data breaches or privilege escalation.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating confidentiality requirements in GDPR and HIPAA. Organizations using affected Apache CXF versions may face compliance violations, potential fines, and reputational damage if exploited.

Mitigation Strategies

Upgrade Apache CXF to versions 4.2.4, 4.1.9, or 3.6.13 to fix the issue. Ensure services using STSTokenValidator do not have alwaysValidateToSts set to false.

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