{"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"}}}}

{}

{"affected": [{"affectedData": [{"product": "picotls", "vendor": "h2o", "versions": [{"status": "affected", "version": "< a06ca417a16f9126808bf5cabe6c5e6e0f16ecae"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "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."}], "id": "CVE-2026-59993", "lastModified": "2026-10-30T21:17:13.193", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-10-30T21:17:13.067", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/h2o/picotls/commit/a06ca417a16f9126808bf5cabe6c5e6e0f16ecae"}, {"source": "security-advisories@github.com", "url": "https://github.com/h2o/picotls/pull/608"}, {"source": "security-advisories@github.com", "url": "https://github.com/h2o/picotls/security/advisories/GHSA-2xcv-h2pg-m99c"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-476"}], "source": "security-advisories@github.com", "type": "Primary"}]}

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