SimpleSAMLphp SAML2: Possible DoS via XPath Transform (CVE-2026-49289) | HOL Guard CVE

High severityCVE-2026-49289GHSA-5CJR-MXJ5-WMRX

SimpleSAMLphp SAML2: Possible DoS via XPath Transform

Answer in brief

CVE-2026-49289 records a High severity vulnerability in SimpleSAMLphp SAML2: Possible DoS via XPath Transform. The current sources do not mark it as known exploited. The current feed maps simplesamlphp/saml2 (composer), simplesamlphp/saml2 (composer), simplesamlphp/saml2 (composer), simplesamlphp/saml2-legacy (composer) and additional mapped packages. Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 19, 2026Updated Aug 19, 2026Source checked Aug 19, 2026First seen by HOL Jul 2, 2026Material review Aug 19, 2026

Upstream Advisory

Key facts

Risk: High
Exploitation: Not marked as known exploited
Affected software: 7 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps simplesamlphp/saml2 (composer), simplesamlphp/saml2 (composer), simplesamlphp/saml2 (composer), simplesamlphp/saml2-legacy (composer) and additional mapped packages. Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
simplesamlphp/saml2composer	<=4.20.2	4.20.3
simplesamlphp/saml2composer	>=4.20.0,<=4.20.2	4.20.3
simplesamlphp/saml2composer	<=4.19.2	4.19.3
simplesamlphp/saml2-legacycomposer	<=4.20.2	4.20.3
simplesamlphp/saml2-legacycomposer	>=4.20.0,<=4.20.2	4.20.3
simplesamlphp/saml2-legacycomposer	<=4.19.2	4.19.3
simplesamlphp/saml2generic	>= 4.19.2, < 4.19.3 \|\| >= 4.20.2, < 4.20.3	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for simplesamlphp/saml2, simplesamlphp/saml2, simplesamlphp/saml2.
Review the reported fix. Update simplesamlphp/saml2 to 4.20.3; simplesamlphp/saml2 to 4.20.3; simplesamlphp/saml2 to 4.19.3; simplesamlphp/saml2-legacy to 4.20.3; simplesamlphp/saml2-legacy to 4.20.3; simplesamlphp/saml2-legacy to 4.19.3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 2, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.