{"cve":"CVE-2026-107301","nvd":{"published":"2026-10-08T17:17:16.143","modified":"2026-10-14T01:17:05.583","status":"Deferred","description":"msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, constructing msgpack5 with an empty or partial options object disables the default protoAction: 'error' protection. A decoded map containing a __proto__ key can then replace the decoded object's prototype, potentially changing inherited properties or downstream behavior, although Object.prototype is not modified globally. This issue is fixed in version 6.1.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L","score":6.5},"cwes":["CWE-1321"],"references":["https://github.com/mcollina/msgpack5/commit/20e82600ac9462e679c8a45e5723315f21e2c774","https://github.com/mcollina/msgpack5/releases/tag/v6.1.0","https://github.com/mcollina/msgpack5/security/advisories/GHSA-8hq7-ggx2-cc6m"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:58:01.639778232+00:00"},"epss":{"cve":"CVE-2026-107301","score":0.00366,"percentile":0.30192,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-8hq7-ggx2-cc6m","url":"https://osv.dev/vulnerability/GHSA-8hq7-ggx2-cc6m","summary":"msgpack5: Partial options disable prototype protection","modified":"2026-10-08T18:00:08.899286917Z","packages":[{"ecosystem":"npm","name":"msgpack5","purl":"pkg:npm/msgpack5","ranges":["<6.1.0"],"fixed":["6.1.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}