{"id":"CVE-2026-114613","state":"PUBLISHED","title":"MessagePack: Unbounded memory leak in msgpack C extension on strict_map_key validation failure","description":"MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.3, the msgpack-python C extension (msgpack._cmsgpack) leaks a decoded map value when deserialization rejects a key with strict_map_key=True (the default). Repeated malformed inputs can cause unbounded process memory growth and denial of service in applications that deserialize attacker-controlled MessagePack data. Both unpackb() and the streaming Unpacker API are affected. The pure-Python fallback does not exhibit this leak in the reported tests. This issue is fixed in version 1.2.3.","publishedAt":"2026-10-22T18:22:40.544Z","updatedAt":"2026-10-23T21:08:06.271Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["msgpack msgpack-python"],"affected":[{"vendor":"msgpack","product":"msgpack-python","versions":[{"version":"< 1.2.3","status":"affected"}]}],"references":["https://github.com/msgpack/msgpack-python/security/advisories/GHSA-j586-36cw-2gc2","https://github.com/msgpack/msgpack-python/commit/620b0eb4c89cd72d4098564537624d9dbb2ce141","https://github.com/msgpack/msgpack-python/releases/tag/v1.2.3"],"weaknesses":["CWE-401"],"ingestedAt":"2026-10-29T20:10:43.281Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/114xxx/CVE-2026-114613.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-114613","state":"PUBLISHED","datePublished":"2026-10-22T18:22:40.544Z","dateUpdated":"2026-10-23T21:08:06.271Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-21T20:34:25.599Z"},"containers":{"cna":{"title":"MessagePack: Unbounded memory leak in msgpack C extension on strict_map_key validation failure","descriptions":[{"lang":"en","value":"MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.3, the msgpack-python C extension (msgpack._cmsgpack) leaks a decoded map value when deserialization rejects a key with strict_map_key=True (the default). Repeated malformed inputs can cause unbounded process memory growth and denial of service in applications that deserialize attacker-controlled MessagePack data. Both unpackb() and the streaming Unpacker API are affected. The pure-Python fallback does not exhibit this leak in the reported tests. This issue is fixed in version 1.2.3."}],"affected":[{"vendor":"msgpack","product":"msgpack-python","versions":[{"version":"< 1.2.3","status":"affected"}]}],"references":[{"url":"https://github.com/msgpack/msgpack-python/security/advisories/GHSA-j586-36cw-2gc2","name":"https://github.com/msgpack/msgpack-python/security/advisories/GHSA-j586-36cw-2gc2","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/msgpack/msgpack-python/commit/620b0eb4c89cd72d4098564537624d9dbb2ce141","name":"https://github.com/msgpack/msgpack-python/commit/620b0eb4c89cd72d4098564537624d9dbb2ce141","tags":["x_refsource_MISC"]},{"url":"https://github.com/msgpack/msgpack-python/releases/tag/v1.2.3","name":"https://github.com/msgpack/msgpack-python/releases/tag/v1.2.3","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-401","lang":"en","description":"CWE-401: Missing Release of Memory after Effective Lifetime","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-22T18:22:40.544Z"},"source":{"advisory":"GHSA-j586-36cw-2gc2","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-23T17:32:58.847580Z","id":"CVE-2026-114613","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-23T21:08:06.271Z"}}]}}}