UBUNTU-CVE-2026-9648 (CVE-2026-9648)

Vulnerability from osv_ubuntu – Published: 2026-06-11 16:16 – Updated: 2026-06-17 04:26 – Source website
VLAI
Details

The crypton-x509-validation Haskell library fails to enforce X.509 NameConstraints, allowing TLS clients to accept certificates whose Subject Alternative Names fall outside the issuing CA’s permitted subtrees. This oversight enables an attacker who compromises a name-constrained sub-CA to impersonate domains beyond its intended scope.

Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libghc-crypton-x509-validation-prof",
            "binary_version": "1.6.12-2build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "haskell-crypton-x509-validation",
        "purl": "pkg:deb/ubuntu/haskell-crypton-x509-validation@1.6.12-2build1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.6.12-1",
        "1.6.12-2",
        "1.6.12-2build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libghc-crypton-x509-validation-prof",
            "binary_version": "1.6.12-3build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "haskell-crypton-x509-validation",
        "purl": "pkg:deb/ubuntu/haskell-crypton-x509-validation@1.6.12-3build1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.6.12-3build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libghc-crypton-x509-validation-prof",
            "binary_version": "1.6.14-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "haskell-crypton-x509-validation",
        "purl": "pkg:deb/ubuntu/haskell-crypton-x509-validation@1.6.14-1build1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.6.12-3build1",
        "1.6.14-1build1"
      ]
    }
  ],
  "aliases": [],
  "details": "The crypton-x509-validation Haskell library fails to enforce X.509 NameConstraints, allowing TLS clients to accept certificates whose Subject Alternative Names fall outside the issuing CA\u2019s permitted subtrees. This oversight enables an attacker who compromises a name-constrained sub-CA to impersonate domains beyond its intended scope.",
  "id": "UBUNTU-CVE-2026-9648",
  "modified": "2026-06-17T04:26:58Z",
  "published": "2026-06-11T16:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-9648"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-9648"
    },
    {
      "type": "REPORT",
      "url": "https://www.kb.cert.org/vuls/id/862559"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/kazu-yamamoto/crypton-certificate/pull/30"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/haskell/security-advisories/pull/332"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/kazu-yamamoto/crypton-certificate/pull/30/changes/f4b77edf6ead77f4a886da40e41eab20f0180e39"
    },
    {
      "type": "REPORT",
      "url": "https://hackage.haskell.org/package/crypton-x509-validation-1.9.1/revisions/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-9648"
  ]
}



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