pyOpenSSL: DTLS cookie callback buffer overflow

A flaw was found in pyOpenSSL. The setcookiegeneratecallback callback function can be used to generate DTLS cookies. When the callback returns a cookie string or byte sequence longer than 256 bytes, a buffer overflow can be triggered due to a missing bounds checking before copying the data to a...

CVE-2026-27459

CVE-2026-27459 affects the pyOpenSSL Python wrapper around OpenSSL. Before 26.0.0, specifically in 22.0.0 through 25.x, a callback provided to set_cookie_generate_callback could return a cookie value >256 bytes, causing an overflow of an OpenSSL buffer. Starting with 26.0.0, such long cookie v...