{"id":"CVE-2026-59876","revision":"2628dd8bbaee479492c745e6f56c7646","records":[{"revision":"2628dd8bbaee479492c745e6f56c7646","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-59876","aliases":[],"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.","state":0,"publishedAt":"2026-07-08T15:31:11.421+00:00","modifiedAt":"2026-07-09T14:41:45.107+00:00","affected":[{"ecosystem":"Vendor product","name":"protobuf.js","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"protobufjs\",\n                    \"product\": \"protobuf.js\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 8.2.0, < 8.6.5\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","score":4.8,"severity":"MEDIUM"}],"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"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-59876","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-59876","identifiers":["CVE-2026-59876"]},"retained":false,"historicalAffected":[]}],"coverage":[]}