{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-55213", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-16T16:16:32.627Z", "datePublished": "2026-07-10T20:49:58.764Z", "dateUpdated": "2026-07-10T20:49:58.764Z"}, "containers": {"cna": {"title": "h2o: musl libc stack overflow (QPACK)", "problemTypes": [{"descriptions": [{"cweId": "CWE-789", "lang": "en", "description": "CWE-789: Memory Allocation with Excessive Size Value", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/h2o/h2o/security/advisories/GHSA-432c-8xmj-frmq", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/h2o/h2o/security/advisories/GHSA-432c-8xmj-frmq"}, {"name": "https://github.com/h2o/h2o/commit/edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1", "tags": ["x_refsource_MISC"], "url": "https://github.com/h2o/h2o/commit/edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1"}], "affected": [{"vendor": "h2o", "product": "h2o", "versions": [{"version": "< edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-07-10T20:49:58.764Z"}, "descriptions": [{"lang": "en", "value": "h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1, when h2o processes a QPACK instruction sent from the peer over HTTP/3, lib/http3/qpack.c might allocate an on-stack buffer as large as approximately 800 KB by calling alloca, which exceeds the default pthread stack size used by musl libc and causes the h2o server to crash with a segmentation fault while touching the guard page. This issue is fixed in commit edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1."}], "source": {"advisory": "GHSA-432c-8xmj-frmq", "discovery": "UNKNOWN"}}}}

{}

{}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "< edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "h2o", "source": "cna", "vendor": "h2o"}, "product": "h2o", "vendor": "h2o"}], "created": "2026-07-10T22:30:04.414340+00:00", "updated": "2026-07-10T22:30:04.414357+00:00", "vendors": ["h2o", "h2o$PRODUCT$h2o"]}