{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-123828", "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "state": "PUBLISHED", "assignerShortName": "openjs", "dateReserved": "2026-11-06T16:02:55.733Z", "datePublished": "2026-11-11T18:10:54.030Z", "dateUpdated": "2026-11-11T18:10:54.030Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "shortName": "openjs", "dateUpdated": "2026-11-11T18:10:54.030Z"}, "title": "Node.js is vulnerable to a heap buffer overflow in HTTP/2 session.altsvc() via a long origin", "descriptions": [{"lang": "en", "value": "A one-byte heap buffer overflow in Node.js HTTP/2 Alt-Svc handling lets a remote, unauthenticated attacker corrupt process memory. When an application passes an attacker-controlled value such as a request's :authority header to Http2Session.altsvc(), the AltSvc implementation in src/node_http2.cc allocates a buffer sized to the origin length and then writes it with a null terminator, placing one byte past the end of the allocation. A single request carrying a long but syntactically valid :authority triggers the out-of-bounds write, which aborts the process and serves as a remote heap-corruption primitive. This vulnerability affects Node.js 26.x and 24.x.", "supportingMedia": [{"type": "text/markdown", "base64": false, "value": "A one-byte heap buffer overflow in Node.js HTTP/2 Alt-Svc handling lets a remote, unauthenticated attacker corrupt process memory. When an application passes an attacker-controlled value such as a request's `:authority` header to `Http2Session.altsvc()`, the AltSvc implementation in `src/node_http2.cc` allocates a buffer sized to the origin length and then writes it with a null terminator, placing one byte past the end of the allocation. A single request carrying a long but syntactically valid `:authority` triggers the out-of-bounds write, which aborts the process and serves as a remote heap-corruption primitive. This vulnerability affects Node.js 26.x and 24.x."}]}], "credits": [{"lang": "en", "value": "zonduu", "type": "reporter"}, {"lang": "en", "value": "mcollina", "type": "remediation developer"}, {"lang": "en", "value": "UlisesGascon", "type": "remediation reviewer"}, {"lang": "en", "value": "pimterry", "type": "remediation reviewer"}, {"lang": "en", "value": "aduh95", "type": "coordinator"}], "affected": [{"vendor": "nodejs", "product": "node", "defaultStatus": "unaffected", "versions": [{"version": "24.0.0", "status": "affected", "lessThan": "24.22.3", "versionType": "semver"}, {"version": "25.0.0", "status": "affected", "lessThan": "26.13.1", "versionType": "semver"}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-122", "description": "Heap Overflow"}]}], "metrics": [{"format": "CVSS", "cvssV3_0": {"version": "3.0", "vectorString": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.9, "baseSeverity": "MEDIUM"}}], "references": [{"url": "https://nodejs.org/en/blog/vulnerability/november-2026-security-releases", "tags": ["vendor-advisory"]}, {"url": "https://cna.openjsf.org/security-advisories.html"}], "x_generator": {"engine": "nodejs-private/security-release publish-cves"}}}}

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