id: PYSEC-2026-1922
published: "2026-07-07T16:02:53.797116Z"
modified: "2026-07-07T17:25:23.985705Z"
aliases:
- CVE-2025-48995
- GHSA-gmhf-gg8w-jw42
summary: SignXML's signature verification with HMAC is vulnerable to a timing attack
details: When verifying signatures with X509 certificate validation turned off and HMAC shared secret set (`signxml.XMLVerifier.verify(require_x509=False, hmac_key=...`), prior versions of SignXML 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.
affected:
- package:
    name: signxml
    ecosystem: PyPI
    purl: pkg:pypi/signxml
  ranges:
  - type: ECOSYSTEM
    events:
    - introduced: "0"
    - fixed: 4.0.4
  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
references:
- type: WEB
  url: https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42
- type: ADVISORY
  url: https://nvd.nist.gov/vuln/detail/CVE-2025-48995
- type: WEB
  url: https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd
- type: PACKAGE
  url: https://github.com/XML-Security/signxml
- type: PACKAGE
  url: https://pypi.org/project/signxml
- type: ADVISORY
  url: https://github.com/advisories/GHSA-gmhf-gg8w-jw42
severity:
- type: CVSS_V4
  score: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N