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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Advisories
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

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History

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

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

Link: CVE-2026-27459

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

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

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

Link: CVE-2026-27459

cve-icon Redhat

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cve-icon OpenCVE Enrichment

No data.

Weaknesses