{"id":"CVE-2026-107297","aliases":["GHSA-gcx5-hxj7-gpqq"],"url":"https://o3.security/vulnerability/CVE-2026-107297","summary":"msgpack5: Quadratic parsing in the streaming decoder","details":"### Impact\n\nThe streaming decoder reparses an incomplete container from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack value across many small chunks, causing quadratic CPU usage and blocking the event loop.\n\n### Patches\n\nThe decoder now preserves incremental container state so completed elements are not parsed again when more input arrives.\n\n### Workarounds\n\nBuffer each complete MessagePack value before decoding it, or limit the number of chunks accepted for a single value.","published":"2026-10-08T17:07:03.740Z","modified":"2026-10-21T02:54:36.439794381Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/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/e4827641d3105e295cbbd56e9c5389978547eab4","label":"mcollina/msgpack5@e482764"},"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-2026-107297.json"},{"type":"ADVISORY","url":"https://github.com/mcollina/msgpack5/security/advisories/GHSA-gcx5-hxj7-gpqq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107297"},{"type":"FIX","url":"https://github.com/mcollina/msgpack5/commit/e4827641d3105e295cbbd56e9c5389978547eab4"},{"type":"PACKAGE","url":"https://github.com/mcollina/msgpack5"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:54:36.439794381Z"}}