CVE-2025-48995

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.

PUBLISHED Reserved 2025-05-29 | Published 2025-06-02 | Updated 2025-06-02 | Assigner GitHub_M

Problem types

CWE-208: Observable Timing Discrepancy

Product status

References

github.com/...ignxml/security/advisories/GHSA-gmhf-gg8w-jw42

github.com/...ommit/1b501faaacf34cf978a52dbc6915ec11e27611cd

cve.org (CVE-2025-48995)

nvd.nist.gov (CVE-2025-48995)

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