CVE-2026-49289

SimpleSAMLphp SAML2: Possible DoS via XPath Transform

Published Aug 19, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. In 4.19.2 and 4.20.2, the library permits attacker-controlled XPath transforms while processing XML signatures in specially crafted SAML messages. XPath evaluation can consume uncontrolled processing resources, allowing a remote unauthenticated attacker to deny service to any entity relying on SimpleSAMLphp or directly on the SAML2 library. The mitigation limits the number of transforms, permits only transform algorithms identified by the SAML 2.0 Core specification, and specifically rejects XPath transforms. This issue is fixed in versions 4.19.3 and 4.20.3.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-5cjr-mxj5-wmrx SimpleSAMLphp has Possible DoS via XPath Transform
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Simplesamlphp
Simplesamlphp saml2
Vendors & Products Simplesamlphp
Simplesamlphp saml2
Type Values Removed Values Added
Description The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. In 4.19.2 and 4.20.2, the library permits attacker-controlled XPath transforms while processing XML signatures in specially crafted SAML messages. XPath evaluation can consume uncontrolled processing resources, allowing a remote unauthenticated attacker to deny service to any entity relying on SimpleSAMLphp or directly on the SAML2 library. The mitigation limits the number of transforms, permits only transform algorithms identified by the SAML 2.0 Core specification, and specifically rejects XPath transforms. This issue is fixed in versions 4.19.3 and 4.20.3.
Title SimpleSAMLphp SAML2: Possible DoS via XPath Transform
Weaknesses CWE-400
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 19, 2026, 6:04 PM
Reserved
May 28, 2026, 8:07 PM
Status
Deferred
Published
Aug 19, 2026, 3:17 PM
Modified
Sep 18, 2026, 8:09 PM