haskell-crypton-x509-validation — security advisory

{
  "id": "bae22739d3d7a1522b18a8d297578ec1a24967a4c763272c2c0ef71443cb6673",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-9648",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-9648",
    "summary": "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.",
    "evidence": "osv:UBUNTU-CVE-2026-9648",
    "products": [
      {
        "name": {
          "value": "haskell-crypton-x509-validation",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.6.12-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.6.12-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1.6.12-2build1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "haskell-crypton-x509-validation",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.6.12-3build1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "haskell-crypton-x509-validation",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.6.14-1build1",
            "evidence": "/affected/2/versions"
          }
        ]
      },
      {
        "name": {
          "value": "haskell-crypton-x509-validation",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.6.12-3build1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "1.6.14-1build1",
            "evidence": "/affected/3/versions"
          }
        ]
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "UBUNTU-CVE-2026-9648",
      "aliases": [
        "UBUNTU-CVE-2026-9648"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "haskell-crypton-x509-validation",
            "purl": "pkg:deb/ubuntu/haskell-crypton-x509-validation?arch=source&distro=noble",
            "ecosystem": "Ubuntu:24.04:LTS"
          },
          "versions": [
            "1.6.12-1",
            "1.6.12-2",
            "1.6.12-2build1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9648.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libghc-crypton-x509-validation-prof",
                "binary_version": "1.6.12-2build1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "haskell-crypton-x509-validation",
            "purl": "pkg:deb/ubuntu/haskell-crypton-x509-validation?arch=source&distro=questing",
            "ecosystem": "Ubuntu:25.10"
          },
          "versions": [
            "1.6.12-3build1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9648.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libghc-crypton-x509-validation-prof",
                "binary_version": "1.6.12-3build1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "haskell-crypton-x509-validation",
            "purl": "pkg:deb/ubuntu/haskell-crypton-x509-validation?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "1.6.14-1build1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9648.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libghc-crypton-x509-validation-prof",
                "binary_version": "1.6.14-1build1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "haskell-crypton-x509-validation",
            "purl": "pkg:deb/ubuntu/haskell-crypton-x509-validation?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "1.6.12-3build1",
            "1.6.14-1build1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9648.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "libghc-crypton-x509-validation-prof",
                "binary_version": "1.6.14-1build1"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T13:01:19.594599428Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-9648"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-9648",
        "https://www.cve.org/CVERecord?id=CVE-2026-9648",
        "https://www.kb.cert.org/vuls/id/862559",
        "https://github.com/kazu-yamamoto/crypton-certificate/pull/30",
        "https://github.com/haskell/security-advisories/pull/332",
        "https://github.com/kazu-yamamoto/crypton-certificate/pull/30/changes/f4b77edf6ead77f4a886da40e41eab20f0180e39",
        "https://hackage.haskell.org/package/crypton-x509-validation-1.9.1/revisions/"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-9648",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 361694,
  "published_at": "2026-06-11T16:16:00+00:00"
}