CVE-2026-44452

{"id": "CVE-2026-44452", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-44452", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-17T14:03:32.725590Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.9, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 2.2}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "h2o", "product": "h2o", "versions": [{"status": "affected", "version": "< 8dc37cb"}]}]}], "published": "2026-07-16T23:16:17.280", "references": [{"url": "https://github.com/h2o/h2o/commit/8dc37cb1e6171f7f772667618ea440696fed82c3", "source": "security-advisories@github.com"}, {"url": "https://github.com/h2o/h2o/security/advisories/GHSA-w68q-rqwx-7wvq", "source": "security-advisories@github.com"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-125"}, {"lang": "en", "value": "CWE-170"}]}], "descriptions": [{"lang": "en", "value": "h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 8dc37cb, when h2o receives a ClientHello message over TLS or QUIC and it contains a zero-length SNI extension, the h2o server runs over the zero-length hostname while trying to copy the hostname, assuming that it is NULL-terminated. This is a potential denial-of-service attack vector in sense that it might trigger segmentation violation. This issue has been fixed by commit 8dc37cb."}], "lastModified": "2026-07-17T18:37:25.590", "sourceIdentifier": "security-advisories@github.com"}