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 `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer. Starting in version 26.0.0, cookie values that are too long are now rejected.
History

Wed, 18 Mar 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Pyca
Pyca pyopenssl
Vendors & Products Pyca
Pyca pyopenssl

Tue, 17 Mar 2026 23:45:00 +0000

Type Values Removed Values Added
Description 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 `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer. Starting in version 26.0.0, cookie values that are too long are now rejected.
Title pyOpenSSL DTLS cookie callback buffer overflow
Weaknesses CWE-120
References
Metrics cvssV4_0

{'score': 7.2, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-17T23:34:28.483Z

Reserved: 2026-02-19T17:25:31.100Z

Link: CVE-2026-27459

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-03-18T00:16:19.273

Modified: 2026-03-18T14:52:44.227

Link: CVE-2026-27459

cve-icon Redhat

No data.