{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-59876","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-07-07T15:41:53.607Z","datePublished":"2026-07-08T15:31:11.421Z","dateUpdated":"2026-07-09T14:41:45.107Z"},"containers":{"cna":{"title":"protobufjs: Text Format string map parsing can mutate returned map object prototype","problemTypes":[{"descriptions":[{"cweId":"CWE-1321","lang":"en","description":"CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.8,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-jfj6-75fj-8934","tags":["x_refsource_CONFIRM"],"url":"https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-jfj6-75fj-8934"},{"name":"https://github.com/protobufjs/protobuf.js/pull/2335","tags":["x_refsource_MISC"],"url":"https://github.com/protobufjs/protobuf.js/pull/2335"},{"name":"https://github.com/protobufjs/protobuf.js/commit/9f97fe413072d3beb52c74e62d88ea8adc9444d8","tags":["x_refsource_MISC"],"url":"https://github.com/protobufjs/protobuf.js/commit/9f97fe413072d3beb52c74e62d88ea8adc9444d8"},{"name":"https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.5","tags":["x_refsource_MISC"],"url":"https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.5"}],"affected":[{"vendor":"protobufjs","product":"protobuf.js","versions":[{"version":">= 8.2.0, < 8.6.5","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-07-08T15:31:11.421Z"},"descriptions":[{"lang":"en","value":"protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 until 8.6.5, the protobufjs Text Format extension parsed string-keyed map entries using ordinary property assignment, allowing a map entry with key __proto__ to change the prototype of the returned map object instead of creating an own map entry in protobufjs/ext/textformat. This issue is fixed in version 8.6.5."}],"source":{"advisory":"GHSA-jfj6-75fj-8934","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-09T14:41:36.435616Z","id":"CVE-2026-59876","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-09T14:41:45.107Z"}}]}}