CVE-2026-27459
pyOpenSSL DTLS cookie callback buffer overflow
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-120 |
| Vendor | pyca |
| Product | pyopenssl |
| Published | Mar 17, 2026 |
| Last Updated | Mar 18, 2026 |
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Affected Versions
pyca / pyopenssl
>= 22.0.0, < 26.0.0