CVSS 4.0
7.2 highCVSS: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:UCVE-2026-27459
High (7.2) in pyopenssl pyopenssl. EPSS 0.7% chance of exploitation in the next 30 days. Fixed in pyopenssl 26.0.0.
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.
Severity
CVSS 3.1
9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- EPSS
- 0.7% chance of exploitation in the next 30 days; higher than 54% of CVEs (scores of 2026-10-31)
- CWE
- CWE-120
- Published
- Modified
- Record from
- the NVD, synced
Affected
- pyopenssl:pyopenssl
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-5pwr-322w-8jr4 | PyPI | pyopenssl | >=22.0.0 <26.0.0 | 26.0.0 |
| PYSEC-2026-2269 | PyPI | pyopenssl | >=22.0.0 <26.0.0 | 26.0.0 |
References
- https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst
- https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408
- https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4
- https://access.redhat.com/errata/RHSA-2026:10754
- https://access.redhat.com/errata/RHSA-2026:11856