pyOpenSSL versions >=22.0.0 and <26.0.0 contain a classic buffer overflow vulnerability (CWE-120) triggered when a user callback to set_cookie_generate_callback returns a cookie value exceeding 256 bytes. This causes an overflow of an OpenSSL buffer. The vulnerability has a CVSS 4.0 base score of 7.2, indicating high severity. The issue is fixed in version 26.0.0 by rejecting overly long cookie values. Red Hat advisories confirm the vulnerability and provide updates for affected products including Red Hat Ansible Automation Platform 2.5 that bundle pyOpenSSL.

An attacker who can control the cookie value returned by the callback may cause a buffer overflow in the OpenSSL buffer used by pyOpenSSL. This could potentially lead to memory corruption, denial of service, or other undefined behavior. The CVSS score of 7.2 reflects a high impact with network attack vector, high complexity, and partial privileges required. There are no known exploits in the wild at this time.

A fixed version of pyOpenSSL is available starting at version 26.0.0, which rejects cookie values longer than 256 bytes, preventing the buffer overflow. Users should upgrade pyOpenSSL to version 26.0.0 or later. Red Hat has issued security advisories and errata with patches for affected products that include pyOpenSSL. Applying these vendor-provided updates is the recommended remediation. Patch status is confirmed by Red Hat advisories linked in the vendor advisory content.