CVE-2026-27459 | pyca pyOpenSSL up to 25.x Cookie set_cookie_generate_callback buffer overflow (GHSA-5pwr-322w-8jr4)

A vulnerability marked as critical has been reported in pyca pyOpenSSL up to 25.x. This affects the function set_cookie_generate_callback of the component Cookie Handler. This manipulation causes buffer overflow.

This vulnerability is tracked as CVE-2026-27459. The attack is possible to be carried out remotely. No exploit exists.

It is suggested to upgrade the affected component.