Apify Model Context Protocol (MCP) server: Actor MCP path authority injection leaks Apify token

Exploitation

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

CVSS

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

EPSS

• CVE-2026-50143: 0.49% estimated exploitation activity in the next 30 days; percentile 42.10 (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.

Actor MCP path authority injection leaks Apify token Summary @apify/actors-mcp-server version 0.10.7 builds Actor standby URLs by directly concatenating a trusted base URL with an attacker-controlled webServerMcpPath value taken from an Actor definition returned by the Apify API. An attacker who publishes a malicious Actor with a crafted webServerMcpPath (e.g., @attacker.example/mcp) can cause the MCP client to resolve the final URL to an entirely different host. Because the MCP client unconditionally attaches the victim's Authorization: Bearer <APIFYTOKEN header to every outbound connection, the victim's Apify API token is exfiltrated to the attacker's server. CVSS Base Score: 8.1 (High). Details getActorMCPServerURL() in src/mcp/actors.ts:44 constructs the Actor standby MCP URL by naive string concatenation: mcpServerPath originates from the webServerMcpPath field of an Actor definition fetched from the Apify API (src/utils/actor.ts:24-28). The field is trimmed and comma-split in…

Published by the source

1 Jul 2026, 22:02 UTC

Last modified by the source

10 Sep 2026, 03:51 UTC

Source last checked

26 Oct 2026, 12:56 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-6gr2-qh89-hxwm

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-6gr2-qh89-hxwm

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# Patch Next advisory brief: CVE-2026-50143

Advisory: Apify Model Context Protocol (MCP) server: Actor MCP path authority injection leaks Apify token
IDs: CVE-2026-50143, GHSA-6gr2-qh89-hxwm
Record: https://patchnext.com/advisories/cve-2026-50143 (revision 2, source checked 26 Oct 2026, 12:56 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @apify/actors-mcp-server 0.10.11. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @apify/actors-mcp-server: affected < 0.10.11; fixed in 0.10.11

## Suggested inspection (read-only)
- `npm ls @apify/actors-mcp-server --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 @apify/actors-mcp-server.
- 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-6gr2-qh89-hxwm (OSV record GHSA-6gr2-qh89-hxwm lists affected ranges: npm @apify/actors-mcp-server >=0 <0.10.11 (fixed))
- Verified: https://github.com/advisories/GHSA-6gr2-qh89-hxwm (GitHub-reviewed advisory GHSA-6gr2-qh89-hxwm lists affected ranges: npm @apify/actors-mcp-server >=0 <0.10.11)

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