{"id":"UBUNTU-CVE-2026-27448","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.","modified":"2026-05-28T15:59:14.728670572Z","published":"2026-03-18T00:00:00Z","related":["USN-8115-1","USN-8335-1"],"upstream":["CVE-2026-27448"],"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"}],"affected":[{"package":{"name":"pyopenssl","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/pyopenssl?arch=source&distro=esm-infra-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.15.1-2ubuntu0.2+esm1"}]}],"versions":["0.15.1-2build1","0.15.1-2ubuntu0.2"],"ecosystem_specific":{"binaries":[{"binary_name":"python-openssl","binary_version":"0.15.1-2ubuntu0.2+esm1"},{"binary_version":"0.15.1-2ubuntu0.2+esm1","binary_name":"python3-openssl"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro","priority_reason":"This has been rated low severity by pyOpenSSL developers"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27448.json"}},{"package":{"name":"pyopenssl","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/pyopenssl?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"17.5.0-1ubuntu1+esm1"}]}],"versions":["16.2.0-1","17.5.0-1","17.5.0-1ubuntu1"],"ecosystem_specific":{"priority_reason":"This has been rated low severity by pyOpenSSL developers","binaries":[{"binary_version":"17.5.0-1ubuntu1+esm1","binary_name":"python-openssl"},{"binary_name":"python3-openssl","binary_version":"17.5.0-1ubuntu1+esm1"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27448.json"}},{"package":{"name":"pyopenssl","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/pyopenssl?arch=source&distro=esm-infra%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"19.0.0-1ubuntu0.1~esm1"}]}],"versions":["19.0.0-1","19.0.0-1build1"],"ecosystem_specific":{"priority_reason":"This has been rated low severity by pyOpenSSL developers","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"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27448.json"}},{"package":{"name":"pyopenssl","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/pyopenssl?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"21.0.0-1ubuntu0.1"}]}],"versions":["20.0.1-1","21.0.0-1"],"ecosystem_specific":{"availability":"No subscription required","priority_reason":"This has been rated low severity by pyOpenSSL developers","binaries":[{"binary_version":"21.0.0-1ubuntu0.1","binary_name":"python3-openssl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27448.json"}},{"package":{"name":"pyopenssl","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/pyopenssl?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"23.2.0-1ubuntu0.1"}]}],"versions":["23.0.0-1","23.2.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-openssl","binary_version":"23.2.0-1ubuntu0.1"}],"availability":"No subscription required","priority_reason":"This has been rated low severity by pyOpenSSL developers"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27448.json"}},{"package":{"name":"pyopenssl","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/pyopenssl?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"25.0.0-1ubuntu0.1"}]}],"versions":["25.0.0-1"],"ecosystem_specific":{"priority_reason":"This has been rated low severity by pyOpenSSL developers","binaries":[{"binary_name":"python3-openssl","binary_version":"25.0.0-1ubuntu0.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27448.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","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_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},{"type":"Ubuntu","score":"low"}]}