pyca/pyopenssl · Security
pyOpenSSL DTLS cookie callback buffer overflow
- GHSA ID
- GHSA-5pwr-322w-8jr4
- CVE ID
- CVE-2026-27459
- Severity
- high
- Published
- Updated
- CVSS v4
- 7.2 · 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
Description
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.
Cookie values that are too long are now rejected.
CWEs
- CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
References
- https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4 ↗
- https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408 ↗
- https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst ↗
- https://nvd.nist.gov/vuln/detail/CVE-2026-27459 ↗
- https://github.com/advisories/GHSA-5pwr-322w-8jr4 ↗