{"id":"CVE-2026-107301","state":"PUBLISHED","title":"msgpack5: Partial options disable prototype protection","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.","publishedAt":"2026-10-08T17:13:00.613Z","updatedAt":"2026-10-14T01:02:53.277Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["mcollina msgpack5"],"affected":[{"vendor":"mcollina","product":"msgpack5","versions":[{"version":"< 6.1.0","status":"affected"}]}],"references":["https://github.com/mcollina/msgpack5/security/advisories/GHSA-8hq7-ggx2-cc6m","https://github.com/mcollina/msgpack5/commit/20e82600ac9462e679c8a45e5723315f21e2c774","https://github.com/mcollina/msgpack5/releases/tag/v6.1.0"],"weaknesses":["CWE-1321"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/107xxx/CVE-2026-107301.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-107301","state":"PUBLISHED","datePublished":"2026-10-08T17:13:00.613Z","dateUpdated":"2026-10-14T01:02:53.277Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-07T15:53:23.587Z"},"containers":{"cna":{"title":"msgpack5: Partial options disable prototype protection","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"mcollina","product":"msgpack5","versions":[{"version":"< 6.1.0","status":"affected"}]}],"references":[{"url":"https://github.com/mcollina/msgpack5/security/advisories/GHSA-8hq7-ggx2-cc6m","name":"https://github.com/mcollina/msgpack5/security/advisories/GHSA-8hq7-ggx2-cc6m","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/mcollina/msgpack5/commit/20e82600ac9462e679c8a45e5723315f21e2c774","name":"https://github.com/mcollina/msgpack5/commit/20e82600ac9462e679c8a45e5723315f21e2c774","tags":["x_refsource_MISC"]},{"url":"https://github.com/mcollina/msgpack5/releases/tag/v6.1.0","name":"https://github.com/mcollina/msgpack5/releases/tag/v6.1.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1321","lang":"en","description":"CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-08T17:13:00.613Z"},"source":{"advisory":"GHSA-8hq7-ggx2-cc6m","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-14T01:02:40.915617Z","id":"CVE-2026-107301","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-14T01:02:53.277Z"}}]}}}