PyPI/pyopenssl CVE-2026-27459: critical 9.8, EPSS 0.73%

pyOpenSSL DTLS cookie callback buffer overflow

Action: Upgrade pyopenssl to 26.0.0 or later.

pip install pyopenssl==26.0.0

Affected

Fixed versions

Sources

• osv: GHSA-5pwr-322w-8jr4
• nvd: CVE-2026-27459
• https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4
• https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408
• https://github.com/pyca/pyopenssl
• https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst

CVE-2026-27459 · published 2026-03-16T16:22:29Z · modified 2026-09-10T03:50:37.586707545Z · JSON