CVE-2025-48995 Information

Description

SignXML is an implementation of the W3C XML Signature standard in Python. When verifying signatures with X509 certificate validation turned off and HMAC shared secret set (signxml.XMLVerifier.verify(require_x509=False hmac_key=...) versions of SignXML prior to 4.0.4 are vulnerable to a potential timing attack. The verifier may leak information about the correct HMAC when comparing it with the user supplied hash allowing users to reconstruct the correct HMAC for any data.

Reference

https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42