GitHub Advisoryadvisory · PyPI
GHSA-5pwr-322w-8jr4 pyOpenSSL DTLS cookie callback buffer overflow
HIGH
Official page ↗
- Aliases
- CVE-2026-27459
- Ecosystem
- PyPI
- Packages
- pyopenssl
- Severity
- High
- CVSS 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
- Weaknesses
- CWE-120
- Reviewed
- 2026-03-16
Affected packages
• PyPI pyopenssl: >= 22.0.0, < 26.0.0 → fixed in 26.0.0
Description
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.
Cookie values that are too long are now rejected.
Related
Alias · CVE (1)
- CVE-2026-27459 pyOpenSSL is a Python wrapper around the OpenSSL library. vulnerability
Weakness · CWE (1)
- CWE-120 Buffer Copy without Checking Size of Input weakness
References
- https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4 web
- https://nvd.nist.gov/vuln/detail/CVE-2026-27459 advisory
- https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408 web
- https://github.com/pyca/pyopenssl package
- https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst web