CVE-2023-49087: Simplesamlphp SAML2

High severity, CVSS 7.5. EPSS: 0.2% chance of exploitation in the next 30 days.

xml-security is a library that implements XML signatures and encryption. Validation of an XML signature requires verification that the hash value of the related XML-document matches a specific DigestValue-value, but also that the cryptographic signature on the SignedInfo-tree (the one that contains the DigestValue) verifies and matches a trusted public key. If an attacker somehow (i.e. by exploiting a bug in PHP's canonicalization function) manages to manipulate the canonicalized version's DigestValue, it would be possible to forge the signature. This issue has been patched in version 1.6.12 and 5.0.0-alpha.13.

Affected products

• Simplesamlphp SAML2: version 5.0.0 only
• Simplesamlphp XML-Security: version 1.6.11 only

Published 2023-11-30. Last modified 2026-06-17.