{"schema_version":"1.7.5","id":"GHSA-5pwr-322w-8jr4","published":"2026-03-16T16:22:29Z","modified":"2026-07-13T07:26:50.550312432Z","aliases":["CVE-2026-27459","PYSEC-2026-2269"],"related":["CGA-qv3q-jpxp-cpmx"],"summary":"pyOpenSSL DTLS cookie callback buffer overflow","details":"If a user provided callback to `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer.\n\nCookie values that are too long are now rejected.","affected":[{"package":{"name":"pyopenssl","ecosystem":"PyPI","purl":"pkg:pypi/pyopenssl"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"22.0.0"},{"fixed":"26.0.0"}]}],"versions":["22.0.0","22.1.0","23.0.0","23.1.0","23.1.1","23.2.0","23.3.0","24.0.0","24.1.0","24.2.1","24.3.0","25.0.0","25.1.0","25.2.0","25.3.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-5pwr-322w-8jr4/GHSA-5pwr-322w-8jr4.json"}}],"references":[{"type":"WEB","url":"https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27459"},{"type":"WEB","url":"https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408"},{"type":"PACKAGE","url":"https://github.com/pyca/pyopenssl"},{"type":"WEB","url":"https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst"}],"database_specific":{"cwe_ids":["CWE-120"],"github_reviewed":true,"github_reviewed_at":"2026-03-16T16:22:29Z","nvd_published_at":"2026-03-18T00:16:19Z","severity":"HIGH"},"severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U"}]}