🛡️ Sentinel: [CRITICAL] Fix prototype pollution in Lua labels#25
🛡️ Sentinel: [CRITICAL] Fix prototype pollution in Lua labels#25ericbfriday wants to merge 1 commit into
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- Changed initialization of `labels` from `{}` to `Object.create ? Object.create(null) : {}` to prevent prototype pollution via user-supplied string keys.
- Added a comment indicating the security mitigation.
- Documented findings in `.jules/sentinel.md`.
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Pull request overview
This PR mitigates a prototype-pollution vector in Lua label handling by changing the internal labels dictionary initialization to use a null-prototype object, and documents the security finding for future reference.
Changes:
- Initialize
FullFlowContext’slabelsdictionary with a null prototype to avoid special keys like__proto__affecting dictionary behavior. - Add an inline security comment in
luaparse.jsdescribing the mitigation. - Add a Sentinel/security writeup documenting the finding and prevention guidance.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| luaparse.js | Switches the labels dictionary initialization to a null-prototype object to mitigate prototype pollution via label names. |
| .jules/sentinel.md | Documents the vulnerability and recommended prevention approach. |
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| var scope = { | ||
| labels: {}, | ||
| // Securely initialize the labels dictionary to prevent prototype pollution via user-supplied Lua labels (e.g., `::__proto__::`) | ||
| labels: Object.create ? Object.create(null) : {}, |
| // Securely initialize the labels dictionary to prevent prototype pollution via user-supplied Lua labels (e.g., `::__proto__::`) | ||
| labels: Object.create ? Object.create(null) : {}, |
| **Vulnerability:** Prototype pollution vulnerability found in how `luaparse.js` handles labels. Lua label nodes were collected into a plain JavaScript object (`{}`) dictionary. When parsed, Lua labels with the name `__proto__` can be abused to poison the global `Object.prototype`. | ||
| **Learning:** Dictionaries storing user-supplied string keys must not be instantiated as plain object literals (`{}`) since it allows accessing and modifying the object prototype via `__proto__`. | ||
| **Prevention:** In environments where we store user-supplied string keys as dictionary keys, objects must be initialized securely. Use `Object.create ? Object.create(null) : {}` as a safer fallback to create a dictionary without a prototype chain, preventing prototype pollution. No newline at end of file |
🚨 Severity: CRITICAL
💡 Vulnerability: Prototype pollution in
luaparse.jswhere user-supplied Lua labels could be abused to poison the globalObject.prototype.🎯 Impact: This could allow arbitrary properties to be injected into the application causing unexpected behavior, potential Denial of Service (DoS), or potentially remote code execution if other gadgets exist.
🔧 Fix: Initialized the
labelsscope dictionary withObject.create(null)instead of an object literal, effectively removing the prototype chain.✅ Verification:
npm run build:packagesandnpm run testpass successfully.PR created automatically by Jules for task 15110526690881242223 started by @ericbfriday