ubuntu-cve-2025-48995
Vulnerability from osv_ubuntu
Published
2025-06-02 17:15
Modified
2026-05-20 15:22
Summary
Details

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.

Severity
6.9 (Medium)
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
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-signxml",
            "binary_version": "4.0.5+dfsg-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "python-signxml",
        "purl": "pkg:deb/ubuntu/python-signxml@4.0.5+dfsg-2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.3+dfsg-1",
        "4.0.5+dfsg-1",
        "4.0.5+dfsg-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-signxml",
            "binary_version": "4.2.0+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "python-signxml",
        "purl": "pkg:deb/ubuntu/python-signxml@4.2.0+dfsg-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.5+dfsg-2",
        "4.2.0+dfsg-1"
      ]
    }
  ],
  "aliases": [],
  "details": "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.",
  "id": "UBUNTU-CVE-2025-48995",
  "modified": "2026-05-20T15:22:53Z",
  "published": "2025-06-02T17:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2025-48995"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-48995"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/XML-Security/signxml/security/advisories/GHSA-gmhf-gg8w-jw42"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/XML-Security/signxml/commit/1b501faaacf34cf978a52dbc6915ec11e27611cd"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "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",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2025-48995"
  ]
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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