Vulnerability 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.
Related Weaknesses (CWE)
References
- https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e
- https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42
FAQ
What is CVE-2025-48995?
CVE-2025-48995 is a documented vulnerability. 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(...
How severe is CVE-2025-48995?
CVSS scoring is not yet available for CVE-2025-48995. Check NVD for updates.
Is there a patch for CVE-2025-48995?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.