{"id":"CVE-2026-107302","aliases":["GHSA-8f34-f56x-9xph"],"url":"https://o3.security/vulnerability/CVE-2026-107302","summary":"msgpack5: Truncated map32 headers throw an unexpected error","details":"### Impact\n\nA truncated `map32` header causes an out-of-bounds buffer read and throws `RangeError` instead of `IncompleteBufferError`. Applications that rely on `IncompleteBufferError` to wait for additional bytes may terminate a request, stream, or worker unexpectedly. No adjacent memory is disclosed because the buffer implementation checks bounds.\n\n### Patches\n\nThe decoder now validates the complete five-byte `map32` header before reading its length and reports truncated input as `IncompleteBufferError`.\n\n### Workarounds\n\nRequire at least five bytes before decoding a value beginning with `0xdf`, or catch `RangeError` and treat it as incomplete input only for truncated `map32` headers.","published":"2026-10-08T17:14:19.514Z","modified":"2026-10-21T02:54:36.448379474Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"msgpack5","fixedVersion":"6.1.0"}],"fix":{"url":"https://github.com/mcollina/msgpack5/commit/15443a1f2aa682a6aa37f1705ac628de5b866ad1","label":"mcollina/msgpack5@15443a1"},"references":[{"type":"WEB","url":"https://github.com/mcollina/msgpack5/releases/tag/v6.1.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107302.json"},{"type":"ADVISORY","url":"https://github.com/mcollina/msgpack5/security/advisories/GHSA-8f34-f56x-9xph"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107302"},{"type":"FIX","url":"https://github.com/mcollina/msgpack5/commit/15443a1f2aa682a6aa37f1705ac628de5b866ad1"},{"type":"PACKAGE","url":"https://github.com/mcollina/msgpack5"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:54:36.448379474Z"}}