CVE-2026-59876 – protobufjs: Text Format string map parsing can mutate returned map object prototype

CVE ID :CVE-2026-59876

Published : July 8, 2026, 3:31 p.m. | 17 minutes ago

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.

Severity: 0.0 | NA

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