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.

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Source ID Title
Github GHSA Github GHSA GHSA-5pwr-322w-8jr4 pyOpenSSL DTLS cookie callback buffer overflow
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 18 Mar 2026 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-18T19:52:15.812Z

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

Link: CVE-2026-27459

cve-icon Vulnrichment

Updated: 2026-03-18T19:52:12.530Z

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.

cve-icon OpenCVE Enrichment

Updated: 2026-03-18T10:42:30Z

Weaknesses