Microsoft Playwright MCP Server vulnerable to DNS Rebinding Attack; Allows Attackers Access to All Server Tools

Exploitation

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

CVSS 4.0

7.2 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L · score source

EPSS

• CVE-2025-9611: 1.22% estimated exploitation activity in the next 30 days; percentile 68.76 (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.

Microsoft Playwright MCP Server versions prior to 0.0.40 fails to validate the Origin header on incoming connections. This allows an attacker to perform a DNS rebinding attack via a victim’s web browser and send unauthorized requests to a locally running MCP server, resulting in unintended invocation of MCP tool endpoints.

Published by the source

7 Jan 2026, 12:31 UTC

Last modified by the source

3 Feb 2026, 03:16 UTC

Source last checked

24 Oct 2026, 22:39 UTC

1. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-6fg3-hvw7-2fwq

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# Patch Next advisory brief: CVE-2025-9611

Advisory: Microsoft Playwright MCP Server vulnerable to DNS Rebinding Attack; Allows Attackers Access to All Server Tools
IDs: CVE-2025-9611, GHSA-6fg3-hvw7-2fwq
Record: https://patchnext.com/advisories/cve-2025-9611 (revision 2, source checked 24 Oct 2026, 22:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @playwright/mcp 0.0.40. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @playwright/mcp: affected < 0.0.40; fixed in 0.0.40

## Suggested inspection (read-only)
- `npm ls @playwright/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 @playwright/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://osv.dev/vulnerability/GHSA-6fg3-hvw7-2fwq (OSV record GHSA-6fg3-hvw7-2fwq lists affected ranges: npm @playwright/mcp >=0 <0.0.40 (fixed))

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