EUVD-2026-12099
GHSA-r353-4845-pr5p
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Lifecycle Timeline
4Description
xml-security is a library that implements XML signatures and encryption. Prior to 2.3.1, XML nodes encrypted with either aes-128-gcm, aes-192-gcm, or aes-256-gcm lack validation of the authentication tag length. An attacker can use this to brute-force an authentication tag, recover the GHASH key, and decrypt the encrypted nodes. It also allows to forge arbitrary ciphertexts without knowing the encryption key. This vulnerability is fixed in 2.3.1.
Analysis
Critical authentication bypass vulnerability in the simplesamlphp/xml-security library (versions before 2.3.1) that affects XML encryption using AES-GCM modes. Attackers can exploit missing authentication tag validation to brute-force decryption keys, decrypt sensitive XML data, and forge arbitrary ciphertexts without knowing encryption keys. …
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Remediation
Within 24 hours: Identify all systems using simplesamlphp/xml-security versions before 2.3.1 and document business criticality; initiate incident response standby. Within 7 days: Implement compensating controls (network segmentation of SAML endpoints, enhanced logging/monitoring for XML processing anomalies); contact vendor for patch timeline and workarounds. …
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External POC / Exploit Code
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