chrome-devtools-mcp: validatePath() does not canonicalize symlinks before enforcing roots

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.1 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L

EPSS

• CVE-2026-53766: 0.12% estimated exploitation activity in the next 30 days; percentile 1.68 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary I originally reported this through Google Bug Hunters. The Google Bug Hunters team said this is in OSS VRP scope but not reward-eligible due to the project tier, and asked me to file an issue or PR directly with this repository. I am reporting it privately here first because it is an unfixed security issue. 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…

Published by the source

17 Aug 2026, 21:56 UTC

Last modified by the source

17 Aug 2026, 21:56 UTC

Source last checked

26 Oct 2026, 13:01 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-8qf9-62x2-82pp

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# Patch Next advisory brief: CVE-2026-53766

Advisory: chrome-devtools-mcp: validatePath() does not canonicalize symlinks before enforcing roots
IDs: CVE-2026-53766, GHSA-8qf9-62x2-82pp
Record: https://patchnext.com/advisories/cve-2026-53766 (revision 1, source checked 26 Oct 2026, 13:01 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: chrome-devtools-mcp 1.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm chrome-devtools-mcp: affected >= 0.24.0, <= 1.0.1; fixed in 1.1.0

## Suggested inspection (read-only)
- `npm ls chrome-devtools-mcp --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on chrome-devtools-mcp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-8qf9-62x2-82pp (GitHub-reviewed advisory GHSA-8qf9-62x2-82pp lists affected ranges: npm chrome-devtools-mcp >=0.24.0 <=1.0.1)

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