提出 #884187: Ractive.js ractive 1.4.4 Prototype Pollution

A prototype pollution vulnerability exists in Ractive 1.4.4.
Ractive exposes public keypath setter APIs such as Ractive#set(). The API accepts string keypaths and keypath maps. During assignment, Ractive splits the provided keypath, resolves intermediate models, and eventually writes the value to the resolved parent object. Prototype-related path segments such as proto, constructor, and prototype are not rejected before the write.
A crafted keypath such as proto.polluted can therefore cause writes to Object.prototype. After exploitation, newly created plain objects may inherit attacker-controlled properties.
The issue was reproduced through public Ractive setter APIs. Additional impact was observed through inherited configuration properties: after polluting Object.prototype.template or Object.prototype.data, later Ractive instances may consume inherited values during initialization, depending on how the application constructs component options.
Affected version:
Ractive 1.4.4
Impact:
Prototype pollution through public keypath setter APIs. Exploitability depends on applications passing untrusted or partially trusted keypaths, keypath maps, dynamic form fields, state sync updates, plugin data, API-driven UI state, or JSON-patch-style updates into Ractive setter APIs.
Recommended fix:
Reject __proto__, constructor, and prototype path segments in all keypath write APIs. Avoid writing through inherited prototype objects. Use own-property checks when reading initialization options such as template and data.

• ソース: ⚠️ https://github.com/ractivejs/ractive/issues/3448
• ユーザー: wjm3 (UID 99672)
• 送信: 2026年07月09日 15:00 (2 月 ago)
• モデレーション: 2026年08月23日 18:07 (2 months later)
• ステータス: 承諾済み
• VulDBエントリ: 394565 [ractivejs ractive 迄 1.4.4 Keypath Ractive#set リモートコード実行]
• ポイント: 20