UBUNTU-CVE-2026-27448 (CVE-2026-27448)

Vulnerability from osv_ubuntu – Published: 2026-03-18 00:00 – Updated: 2026-05-28 15:34 – Source website
VLAI
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.

Severity
1.7 (Low)
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
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
N/A (UNKNOWN)
low
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "python-openssl",
            "binary_version": "0.15.1-2ubuntu0.2+esm1"
          },
          {
            "binary_name": "python3-openssl",
            "binary_version": "0.15.1-2ubuntu0.2+esm1"
          }
        ],
        "priority_reason": "This has been rated low severity by pyOpenSSL developers"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "pyopenssl",
        "purl": "pkg:deb/ubuntu/pyopenssl@0.15.1-2ubuntu0.2+esm1?arch=source\u0026distro=esm-infra-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.15.1-2ubuntu0.2+esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.15.1-2build1",
        "0.15.1-2ubuntu0.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "python-openssl",
            "binary_version": "17.5.0-1ubuntu1+esm1"
          },
          {
            "binary_name": "python3-openssl",
            "binary_version": "17.5.0-1ubuntu1+esm1"
          }
        ],
        "priority_reason": "This has been rated low severity by pyOpenSSL developers"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "pyopenssl",
        "purl": "pkg:deb/ubuntu/pyopenssl@17.5.0-1ubuntu1+esm1?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "17.5.0-1ubuntu1+esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "16.2.0-1",
        "17.5.0-1",
        "17.5.0-1ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "python-openssl",
            "binary_version": "19.0.0-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "python3-openssl",
            "binary_version": "19.0.0-1ubuntu0.1~esm1"
          }
        ],
        "priority_reason": "This has been rated low severity by pyOpenSSL developers"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "pyopenssl",
        "purl": "pkg:deb/ubuntu/pyopenssl@19.0.0-1ubuntu0.1~esm1?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "19.0.0-1ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "19.0.0-1",
        "19.0.0-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-openssl",
            "binary_version": "21.0.0-1ubuntu0.1"
          }
        ],
        "priority_reason": "This has been rated low severity by pyOpenSSL developers"
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "pyopenssl",
        "purl": "pkg:deb/ubuntu/pyopenssl@21.0.0-1ubuntu0.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "21.0.0-1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "20.0.1-1",
        "21.0.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-openssl",
            "binary_version": "23.2.0-1ubuntu0.1"
          }
        ],
        "priority_reason": "This has been rated low severity by pyOpenSSL developers"
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "pyopenssl",
        "purl": "pkg:deb/ubuntu/pyopenssl@23.2.0-1ubuntu0.1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "23.2.0-1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "23.0.0-1",
        "23.2.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-openssl",
            "binary_version": "25.0.0-1ubuntu0.1"
          }
        ],
        "priority_reason": "This has been rated low severity by pyOpenSSL developers"
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "pyopenssl",
        "purl": "pkg:deb/ubuntu/pyopenssl@25.0.0-1ubuntu0.1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "25.0.0-1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "25.0.0-1"
      ]
    }
  ],
  "aliases": [],
  "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": "UBUNTU-CVE-2026-27448",
  "modified": "2026-05-28T15:34:52Z",
  "published": "2026-03-18T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-27448"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-27448"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8115-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8335-1"
    }
  ],
  "related": [
    "USN-8115-1",
    "USN-8335-1"
  ],
  "schema_version": "1.7.0",
  "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"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "low",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-27448"
  ]
}



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