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CVE-2026-27459

pyOpenSSL DTLS cookie callback buffer overflow

CVSS 4.0 7.2 HIGHCheck source for fixed versionsKEV status unknown
Original advisory

cve-program · CVE-2026-27459

Published

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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Affected versions, risk and source history

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cve-program · CVE-2026-27459

Published

pyOpenSSL DTLS cookie callback buffer overflow

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.

Source published
17 Mar 2026 23:34:28 UTC
Source modified
11 Sep 2026 12:09:00 UTC
Saved here
23 Oct 2026 15:48:27 UTC
Source terms
CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · 7.2 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

ChangeIntel

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Sources read 14 Nov 23:34 UTC · 274 of 275 readable · 272 fully read · documentation 469/469 current

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