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CVE-2025-48995

CVE-2025-48995 · SignXML's signature verification with HMAC is vulnerable to a timing attack

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 6.9 · Medium · EPSS 0.2% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • signxml

    Versions
    • < 4.0.4: Affected

    No fix published

  • python-signxml Debian:13

    Affected ranges
    • ECOSYSTEM: < 4.0.5+dfsg-1

    Update to 4.0.5+dfsg-1

  • python-signxml Debian:14

    Affected ranges
    • ECOSYSTEM: < 4.0.5+dfsg-1

    Update to 4.0.5+dfsg-1

  • signxml PyPI

    Versions
    • 0.0.1
    • 0.1.0
    • 0.1.1
    • 0.1.2
    • 0.1.3
    • 0.1.4
    • 0.1.5
    • 0.1.6
    • 0.1.7
    • 0.1.8
    • 0.1.9
    • 0.2.0
    • 0.2.1
    • 0.2.2
    • 0.2.3
    • 0.2.4
    • 0.2.5
    • 0.2.6
    • 0.2.7
    • 0.2.8
    • 0.2.9
    • 0.3.0
    • 0.3.1
    • 0.3.2
    • 0.3.3
    • 0.3.4
    • 0.3.5
    • 0.3.6
    • 0.3.7
    • 0.3.8
    • 0.3.9
    • 0.4.0
    • 0.4.1
    • 0.4.2
    • 0.4.3
    • 0.4.4
    • 0.4.5
    • 0.4.6
    • 0.5.0
    • 0.6.0
    • 1.0.0
    • 1.0.1
    • 1.0.2
    • 2.0.0
    • 2.1.4
    • 2.10.0
    • 2.10.1
    • 2.2.0
    • 2.2.1
    • 2.2.2
    • 2.2.3
    • 2.2.4
    • 2.2.6
    • 2.3.0
    • 2.4.0
    • 2.5.2
    • 2.6.0
    • 2.7.0
    • 2.7.1
    • 2.7.2
    • 2.7.3
    • 2.8.0
    • 2.8.1
    • 2.8.2
    • 2.9.0
    • 3.0.0
    • 3.0.1
    • 3.0.2
    • 3.1.0
    • 3.1.1
    • 3.2.0
    • 3.2.1
    • 3.2.2
    • 4.0.0
    • 4.0.1
    • 4.0.2
    • 4.0.3
    Affected ranges
    • ECOSYSTEM: < 4.0.4

    Update to 4.0.4

  • python-signxml Ubuntu:25.10

    Versions
    • 4.0.3+dfsg-1
    • 4.0.5+dfsg-1
    • 4.0.5+dfsg-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-signxml Ubuntu:26.10

    Versions
    • 4.2.0+dfsg-1
    • 4.4.0+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-signxml Ubuntu:26.04:LTS

    Versions
    • 4.0.5+dfsg-2
    • 4.2.0+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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