CVE-2026-27459 pyOpenSSL DTLS cookie callback buffer overflow

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 setcookiegeneratecallback returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer. Starting in version 26.0....

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...