CVE-2026-53766
MEDIUMCVE-2026-53766 is a medium-severity (CVSS 6.1) Path Traversal vulnerability in chrome-devtools-mcp. O3 Security confirms whether CVE-2026-53766 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
chrome-devtools-mcp: validatePath() does not canonicalize symlinks before enforcing roots
Real-World Exposure
chrome-devtools-mcpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Chrome DevTools for agents (chrome-devtools-mcp) lets your coding agent control and inspect a live Chrome browser. From 0.24.0 until 1.1.0, McpContext.validatePath() enforces workspace roots by checking whether path.resolve(filePath) textually falls under one of the configured root paths. path.resolve() does not canonicalize symbolic links. As a result, a symlink inside a configured workspace root can point to a file outside that root, pass validation, and then be followed by downstream file read/write operations. This bypass applies even when the MCP client correctly declares the roots capability with a non-empty list. It is separate from the documented legacy behavior where missing roots capability allows all paths. The practical impact is a workspace-boundary bypass. In the write direction, filePath-writing tools can overwrite out-of-root files through an in-root symlink. In the read direction, upload_file can read through the symlink and send the file to the currently selected web page. This vulnerability is fixed in 1.1.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | chrome-devtools-mcp | ≥ 0.24.0&&< 1.1.0 | 1.1.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for chrome-devtools-mcp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update chrome-devtools-mcp to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-53766 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-53766 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-53766. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-53766 in your dependencies?
O3 detects CVE-2026-53766 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.