medium6.5
CVE-2026-59993
Picotls is a TLS protocol library that allows users select different crypto backends based on their use case.
Impact
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.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| H2o | Picotls | before a06ca417a16f9126808bf5cabe6c5e6e0f16ecae |