Vulnerability Description
Picotls is a TLS protocol library that allows users select different crypto backends based on their use case. In affected revisions through 44bc503, when picotls is used as a `client-side TLS stack`, a peer can send a `HelloRetryRequest` followed by a `spoofed Hello message` that causes a null-pointer dereference. This can terminate the consuming process, including a process performing other work, resulting in denial of service. This issue is fixed in commit a06ca41.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/h2o/picotls/commit/a06ca417a16f9126808bf5cabe6c5e6e0f16ecae
- https://github.com/h2o/picotls/pull/608
- https://github.com/h2o/picotls/security/advisories/GHSA-2xcv-h2pg-m99c
FAQ
What is CVE-2026-59993?
CVE-2026-59993 is a vulnerability with a CVSS score of 6.5 (MEDIUM). Picotls is a TLS protocol library that allows users select different crypto backends based on their use case. In affected revisions through 44bc503, when picotls is used as a `client-side TLS stack`, ...
How severe is CVE-2026-59993?
CVE-2026-59993 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-59993?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.