Vulnerability · Published Aug 19, 2026 · Assigned by GitHub_M
CVE-2026-49289SimpleSAMLphp SAML2: Possible DoS via XPath Transform
High 7.5
In plain English
A high-severity uncontrolled resource consumption in saml2 from simplesamlphp. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 56% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | simplesamlphp | no fix listed | DEBIAN-CVE-2026-49289 |
| Debian:14 | simplesamlphp | no fix listed | DEBIAN-CVE-2026-49289 |
| Packagist | simplesamlphp/saml2 | 4.20.3 | GHSA-5cjr-mxj5-wmrx |
| Packagist | simplesamlphp/saml2 | 4.19.3 | GHSA-5cjr-mxj5-wmrx |
| Packagist | simplesamlphp/saml2-legacy | 4.19.3 | GHSA-5cjr-mxj5-wmrx |
| Packagist | simplesamlphp/saml2-legacy | 4.20.3 | GHSA-5cjr-mxj5-wmrx |
| Ubuntu:24.04:LTS | simplesamlphp | no fix listed | UBUNTU-CVE-2026-49289 |
| Ubuntu:26.04:LTS | simplesamlphp | no fix listed | UBUNTU-CVE-2026-49289 |
| Ubuntu:26.10 | simplesamlphp | no fix listed | UBUNTU-CVE-2026-49289 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| simplesamlphp | saml2 | >= 4.19.2, < 4.19.3>= 4.20.2, < 4.20.3 |
Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/simplesamlphp/saml2/security/advisories/GHSA-5cjr-mxj5-wmrx x_refsource_CONFIRM
- https://github.com/simplesamlphp/saml2/commit/0043033891fdba9618386ab583e1d8afdf8aea6e x_refsource_MISC
- https://github.com/simplesamlphp/saml2/commit/6695eb923da491f716009c2a26b34a463ac05c6b x_refsource_MISC