{"id":"CVE-2026-59876","state":"PUBLISHED","title":"protobufjs: Text Format string map parsing can mutate returned map object prototype","description":"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.","publishedAt":"2026-07-08T15:31:11.421Z","updatedAt":"2026-07-09T14:41:45.107Z","severity":{"score":4.8,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["protobufjs protobuf.js"],"affected":[{"vendor":"protobufjs","product":"protobuf.js","versions":[{"version":">= 8.2.0, < 8.6.5","status":"affected"}]}],"references":["https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-jfj6-75fj-8934","https://github.com/protobufjs/protobuf.js/pull/2335","https://github.com/protobufjs/protobuf.js/commit/9f97fe413072d3beb52c74e62d88ea8adc9444d8","https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.5"],"weaknesses":["CWE-1321"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/59xxx/CVE-2026-59876.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-59876","state":"PUBLISHED","datePublished":"2026-07-08T15:31:11.421Z","dateUpdated":"2026-07-09T14:41:45.107Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-07T15:41:53.607Z"},"containers":{"cna":{"title":"protobufjs: Text Format string map parsing can mutate returned map object prototype","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."}],"affected":[{"vendor":"protobufjs","product":"protobuf.js","versions":[{"version":">= 8.2.0, < 8.6.5","status":"affected"}]}],"references":[{"url":"https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-jfj6-75fj-8934","name":"https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-jfj6-75fj-8934","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/protobufjs/protobuf.js/pull/2335","name":"https://github.com/protobufjs/protobuf.js/pull/2335","tags":["x_refsource_MISC"]},{"url":"https://github.com/protobufjs/protobuf.js/commit/9f97fe413072d3beb52c74e62d88ea8adc9444d8","name":"https://github.com/protobufjs/protobuf.js/commit/9f97fe413072d3beb52c74e62d88ea8adc9444d8","tags":["x_refsource_MISC"]},{"url":"https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.5","name":"https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.5","tags":["x_refsource_MISC"]}],"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"}}],"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":"2026-07-08T15:31:11.421Z"},"source":{"advisory":"GHSA-jfj6-75fj-8934","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","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"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-09T14:41:45.107Z"}}]}}}