Apify Model Context Protocol (MCP) server: Domain Allowlist Bypass in fetch-apify-docs via String Prefix Matching

Description

The fetch-apify-docs tool validates URLs against a domain allowlist using String.startsWith() instead of proper URL hostname comparison. This allows bypass via attacker-controlled subdomains (e.g., https://docs.apify.com.evil.com/), enabling the tool to fetch and return arbitrary web content to the LLM.

Recommendation

Update the @apify/actors-mcp-server package to the latest compatible version. Followings are version details:

• Affected version(s): < 0.9.21
• Patched version(s): 0.9.21

References

• GHSA-jwp7-wg77-3w9v
• CVE-2026-46341
• CWE-183
• CWE-20
• CAPEC-310
• OWASP 2021-A3
• OWASP 2021-A4
• OWASP 2021-A6

Related Issues

• Feathers has an origin validation bypass via prefix matching - CVE-2026-27192
• Parse Server has Denial of Service (DoS) and Cloud Function Dispatch Bypass via Prototype Chain Resolution - CVE-2026-30939
• Parse Server has an auth provider validation bypass on login via partial authData - CVE-2026-33409
• Signal K Server: Arbitrary Prototype Read via `from` Field Bypass - CVE-2026-35038

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Tags:

npm

@apify/actors-mcp-server