{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-59993","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-07-07T19:41:00.005Z","datePublished":"2026-10-30T21:01:54.818Z","dateUpdated":"2026-10-30T21:01:54.818Z"},"containers":{"cna":{"title":"Picotls has NULL pointer dereference during handshake, when running as a client","problemTypes":[{"descriptions":[{"cweId":"CWE-476","lang":"en","description":"CWE-476: NULL Pointer Dereference","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"name":"https://github.com/h2o/picotls/security/advisories/GHSA-2xcv-h2pg-m99c","tags":["x_refsource_CONFIRM"],"url":"https://github.com/h2o/picotls/security/advisories/GHSA-2xcv-h2pg-m99c"},{"name":"https://github.com/h2o/picotls/pull/608","tags":["x_refsource_MISC"],"url":"https://github.com/h2o/picotls/pull/608"},{"name":"https://github.com/h2o/picotls/commit/a06ca417a16f9126808bf5cabe6c5e6e0f16ecae","tags":["x_refsource_MISC"],"url":"https://github.com/h2o/picotls/commit/a06ca417a16f9126808bf5cabe6c5e6e0f16ecae"}],"affected":[{"vendor":"h2o","product":"picotls","versions":[{"version":"< a06ca417a16f9126808bf5cabe6c5e6e0f16ecae","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-10-30T21:01:54.818Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-2xcv-h2pg-m99c","discovery":"UNKNOWN"}}}}