{"id":"CVE-2026-27459","summary":"pyOpenSSL DTLS cookie callback buffer overflow","details":"pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 22.0.0 and prior to version 26.0.0, 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. Starting in version 26.0.0, cookie values that are too long are now rejected.","aliases":["GHSA-5pwr-322w-8jr4","PYSEC-2026-2269"],"modified":"2026-08-04T03:32:45.480344710Z","published":"2026-03-17T23:34:28.483Z","related":["CGA-qv3q-jpxp-cpmx","SUSE-EL-9-CLIENT-TOOLS-2026-2255","SUSE-RU-2026:2769-1","SUSE-SU-2026:1192-1","SUSE-SU-2026:20930-1","SUSE-SU-2026:20954-1","SUSE-SU-2026:20960-1","SUSE-SU-2026:21990-1","SUSE-SU-2026:2242-1","SUSE-SU-2026:2244-1","SUSE-SU-2026:2255-1","openSUSE-SU-2026:10392-1","openSUSE-SU-2026:20419-1"],"database_specific":{"cwe_ids":["CWE-120"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27459.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27459.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:10754"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:11856"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:11916"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:11996"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:13508"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:13512"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:13545"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:13553"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:14835"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:14873"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:14874"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:19375"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:21017"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:22465"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:24853"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:48085"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:7224"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:8437"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-27459"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27459.json"},{"type":"ADVISORY","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":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2448503"},{"type":"FIX","url":"https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/pyca/pyopenssl","events":[{"introduced":"819095fa886db98cf43b6f0e66ba19c83d64d3c0"},{"fixed":"358cbf29c4e364c59930e53a270116249581eaa3"},{"fixed":"57f09bb4bb051d3bc2a1abd36e9525313d5cd408"}],"database_specific":{"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:pyopenssl:pyopenssl:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"22.0.0"},{"fixed":"26.0.0"}]}}],"versions":["25.3.0","25.2.0","25.1.0","25.0.0","24.3.0","24.2.1","24.2.0","24.1.0","24.0.0","23.3.0","23.2.0","23.1.0","23.0.0","22.1.0","22.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27459.json"}}],"schema_version":"1.8.0","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"}]}