{"id":"CVE-2026-107299","state":"PUBLISHED","title":"msgpack5: Reserved byte can cause unbounded stream buffering","description":"msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder treats the reserved MessagePack byte 0xc1 as incomplete input instead of invalid input. When 0xc1 begins a stream, subsequent data remains buffered while the decoder waits for bytes that cannot make the value valid, allowing a remote peer to exhaust memory. This issue is fixed in version 6.1.0.","publishedAt":"2026-10-08T17:09:47.191Z","updatedAt":"2026-10-09T15:15:00.980Z","severity":{"score":5.9,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","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-26wq-p25c-j6fv","https://github.com/mcollina/msgpack5/commit/85da345bf1acc18ca441741e5cf4aa0ed0d69314","https://github.com/mcollina/msgpack5/releases/tag/v6.1.0"],"weaknesses":["CWE-228"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/107xxx/CVE-2026-107299.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-107299","state":"PUBLISHED","datePublished":"2026-10-08T17:09:47.191Z","dateUpdated":"2026-10-09T15:15:00.980Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-07T15:53:23.587Z"},"containers":{"cna":{"title":"msgpack5: Reserved byte can cause unbounded stream buffering","descriptions":[{"lang":"en","value":"msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder treats the reserved MessagePack byte 0xc1 as incomplete input instead of invalid input. When 0xc1 begins a stream, subsequent data remains buffered while the decoder waits for bytes that cannot make the value valid, allowing a remote peer to exhaust memory. 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-26wq-p25c-j6fv","name":"https://github.com/mcollina/msgpack5/security/advisories/GHSA-26wq-p25c-j6fv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/mcollina/msgpack5/commit/85da345bf1acc18ca441741e5cf4aa0ed0d69314","name":"https://github.com/mcollina/msgpack5/commit/85da345bf1acc18ca441741e5cf4aa0ed0d69314","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":"HIGH","baseScore":5.9,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-228","lang":"en","description":"CWE-228: Improper Handling of Syntactically Invalid Structure","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-08T17:09:47.191Z"},"source":{"advisory":"GHSA-26wq-p25c-j6fv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-08T20:23:17.872522Z","id":"CVE-2026-107299","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":"2026-10-09T15:15:00.980Z"}}]}}}