{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "358cbf29c4e364c59930e53a270116249581eaa3"
            }
          ],
          "repo": "https://github.com/pyca/pyopenssl",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-vp96-hxj8-p424"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-636"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27448.json"
  },
  "details": "pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 0.14.0 and prior to version 26.0.0, if a user provided callback to `set_tlsext_servername_callback` raised an unhandled exception, this would result in a connection being accepted. If a user was relying on this callback for any security-sensitive behavior, this could allow bypassing it. Starting in version 26.0.0, unhandled exceptions now result in rejecting the connection.",
  "id": "CVE-2026-27448",
  "modified": "2026-04-01T23:09:10.869193246Z",
  "published": "2026-03-17T23:24:30.661Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst#L27"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27448.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27448"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pyca/pyopenssl/commit/d41a814759a9fb49584ca8ab3f7295de49a85aa0"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U",
      "type": "CVSS_V4"
    }
  ],
  "summary": "pyOpenSSL allows TLS connection bypass via unhandled callback exception in set_tlsext_servername_callback"
}