Critical · published March 18, 2026
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.
| Product | Versions | Fixed in |
|---|---|---|
| pyopenssl/pyopenssl | ≥ 22.0.0, < 26.0.0 | 26.0.0 |