It was discovered that pyOpenSSL incorrectly handled exceptions in the tlsext_servername callback. This could result in connections being accepted after an exception, contrary to expectations. (CVE-2026-27448) It was discovered that pyOpenSSL incorrectly handled the DTLS cookie generation callback. If a callback provided cookie values greater than 256 bytes, an attacker could use this issue to cause pyOpenSSL to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 25.10. (CVE-2026-27459)