{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "picotls",
          "vendor": "h2o",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c a06ca417a16f9126808bf5cabe6c5e6e0f16ecae"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "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"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-476",
              "description": "CWE-476: NULL Pointer Dereference",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T21:01:54.818Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "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"
        }
      ],
      "source": {
        "advisory": "GHSA-2xcv-h2pg-m99c",
        "discovery": "UNKNOWN"
      },
      "title": "Picotls has NULL pointer dereference during handshake, when running as a client"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-59993",
    "datePublished": "2026-10-30T21:01:54.818Z",
    "dateReserved": "2026-07-07T19:41:00.005Z",
    "dateUpdated": "2026-10-30T21:01:54.818Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}