CVE-2026-25587: Prototype Guard Unsafe Hasownproperty Instance Method
Calling `.hasOwnProperty()` as an instance method in a function-property mutation guard is unsafe in sandbox or access-control code. When the guarded object is itself a prototype (e.g., `Map.prototype`), its built-in methods ARE own properties. As a result, `!obj.hasOwnProperty(prop)` evaluates to `false` and the guard silently permits the overwrite. This al
JSgreprules fetch cve-2026-25587-prototype-guard-unsafe-hasownproperty-instance-method --engine opengrepDescription
Calling `.hasOwnProperty()` as an instance method in a function-property mutation guard is unsafe in sandbox or access-control code. When the guarded object is itself a prototype (e.g., `Map.prototype`), its built-in methods ARE own properties. As a result, `!obj.hasOwnProperty(prop)` evaluates to `false` and the guard silently permits the overwrite. This al
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