Submit #857043: Node.js @carto/api-client 0.5.29 Prototype Pollution

@carto/api-client exposes addFilter(filters, options) for adding filters to a filter object. The column option is used directly as a dynamic property name on a normal object. Passing column: "__proto__" causes the function to write the filter data onto Object.prototype.
The vulnerable logic is in src/filters.ts:
export function addFilter(
filters: Record<string, Filter>,
{column, type, values, owner}: AddFilterOptions
): Record<string, Filter> {
if (!filters[column]) {
filters[column] = {};
}

const filter = {values, owner} as FilterTypeOptions<typeof type>;
(filters[column][type] as FilterTypeOptions<typeof type>) = filter;

return filters;
}
When column is __proto__, filters[column] resolves to Object.prototype instead of a safe own property on filters. The guard therefore does not create a new own object:

• Source: ⚠️ https://github.com/CartoDB/carto-api-client/issues/299
• User: wjm1 (UID 98929)
• Submission: 06/12/2026 15:35 (1 month ago)
• Moderation: 07/17/2026 21:30 (1 month later)
• Status: Accepted
• VulDB entry: 379917 [CartoDB carto-api-client 0.5.29 src/filters.ts addFilter column prototype pollution]
• Points: 20