{"cve":"CVE-2026-27459","nvd":{"published":"2026-03-18T00:16:19.273","modified":"2026-09-10T13:17:59.900","status":"Modified","description":"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.","cvss_v4":{"vector":"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","score":7.2},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-120"],"references":["https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst","https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408","https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4","https://access.redhat.com/errata/RHSA-2026:10754","https://access.redhat.com/errata/RHSA-2026:11856"],"products":["pyopenssl:pyopenssl"],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-27459","score":0.00731,"percentile":0.54324,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-5pwr-322w-8jr4","url":"https://osv.dev/vulnerability/GHSA-5pwr-322w-8jr4","summary":"pyOpenSSL DTLS cookie callback buffer overflow","modified":"2026-09-10T03:50:37.586707545Z","packages":[{"ecosystem":"PyPI","name":"pyopenssl","purl":"pkg:pypi/pyopenssl","ranges":[">=22.0.0 <26.0.0"],"fixed":["26.0.0"]}]},{"id":"PYSEC-2026-2269","url":"https://osv.dev/vulnerability/PYSEC-2026-2269","summary":"","modified":"2026-07-13T07:15:42.174035827Z","packages":[{"ecosystem":"PyPI","name":"pyopenssl","purl":"pkg:pypi/pyopenssl","ranges":[">=22.0.0 <26.0.0"],"fixed":["26.0.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}