{"id":"CVE-2026-59993","aliases":[],"cve":{"records":[{"id":"CVE-2026-59993","source":"GitHub_M","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-07-07T19:41:00.005Z","published":"2026-10-30T21:01:54.818Z","modified":"2026-10-30T21:01:54.818Z"}],"publishers":[{"name":"GitHub_M","role":"CNA","organizationId":"a0819718-46f1-4df5-94e2-005712e83aaa","modified":"2026-10-30T21:01:54.818Z"}],"references":[{"url":"https://github.com/h2o/picotls/security/advisories/GHSA-2xcv-h2pg-m99c","tags":["x_refsource_CONFIRM"],"source":"GitHub_M"},{"url":"https://github.com/h2o/picotls/pull/608","tags":["x_refsource_MISC"],"source":"GitHub_M"},{"url":"https://github.com/h2o/picotls/commit/a06ca417a16f9126808bf5cabe6c5e6e0f16ecae","tags":["x_refsource_MISC"],"source":"GitHub_M"}],"weaknesses":[{"id":"CWE-476","description":"CWE-476: NULL Pointer Dereference","source":"GitHub_M"}],"applicability":[],"prioritization":[]},"title":"Picotls has NULL pointer dereference during handshake, when running as a client","titleSource":"GitHub_M","descriptionSource":"GitHub_M","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a06ca41.","score":6.5,"severity":"medium","published":"2026-10-30T21:01:54.818Z","modified":"2026-10-30T21:01:54.818Z","withdrawn":false,"knownExploited":false,"affected":[],"products":[{"vendor":"h2o","name":"picotls","platforms":[],"versions":[{"version":"< a06ca417a16f9126808bf5cabe6c5e6e0f16ecae","status":"affected"}],"cpes":[],"source":"GitHub_M","url":"https://www.cve.org/CVERecord?id=CVE-2026-59993"}],"remediation":[],"references":["https://github.com/h2o/picotls/security/advisories/GHSA-2xcv-h2pg-m99c","https://github.com/h2o/picotls/pull/608","https://github.com/h2o/picotls/commit/a06ca417a16f9126808bf5cabe6c5e6e0f16ecae"],"sources":[{"name":"CVE","id":"CVE-2026-59993","modified":"2026-10-30T21:01:54.818Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-59993"}],"assessments":[{"source":"GitHub_M","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","score":6.5}],"sourceAffected":[],"observedAt":"2026-10-30T21:32:01.809Z","kev":{"status":"not-listed","checkedAt":"2026-10-31T11:25:31.829Z"},"coverage":[{"source":"NVD","status":"available","checkedAt":"2026-10-30T21:40:35.171Z","attemptedAt":"2026-10-30T21:40:35.171Z"},{"source":"GHSA","status":"no-result","checkedAt":"2026-10-30T21:40:35.628Z","attemptedAt":"2026-10-30T21:40:35.628Z"},{"source":"EUVD","status":"no-result","checkedAt":"2026-10-30T21:40:37.734Z","attemptedAt":"2026-10-30T21:40:37.734Z"},{"source":"EPSS","status":"no-result","checkedAt":"2026-10-30T21:40:35.267Z","attemptedAt":"2026-10-30T21:40:35.267Z"}],"evidence":[{"source":"NVD","id":"CVE-2026-59993","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59993","modified":"2026-10-30T21:17:13.193","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","checkedAt":"2026-10-30T21:40:35.171Z"}],"aiSummary":{"text":"Picotls, a TLS protocol library, has a NULL pointer dereference weakness when used as a client, allowing a peer to cause a denial of service via a HelloRetryRequest and spoofed Hello message. Affected versions are prior to commit a06ca41. This can terminate the consuming process.","model":"@cf/meta/llama-3.3-70b-instruct-fp8-fast","generatedAt":"2026-10-31T07:01:34.653Z","sources":[{"name":"CVE","url":"https://www.cve.org/CVERecord?id=CVE-2026-59993"}]}}