Resource exhaustion in Simplesamlphp Saml2
CVE-2026-49289
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.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.008 (54.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 54.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.008 · change: +0.002
Affected products
- Simplesamlphp Saml2 — versions >= 4.19.2, < 4.19.3, >= 4.20.2, < 4.20.3
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-49289?
- CVE-2026-49289 is a high-severity vulnerability in Simplesamlphp Saml2, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-08-19.
- How severe is CVE-2026-49289?
- High severity. CVSS v3 base score is 7.5 out of 10.