fix UI redressing vulnerability

[0xcucumbersalad]

What is this contribution about?

This PR mitigates UI redressing (clickjacking) attacks against the MCP Mesh admin interface by adding X-Frame-Options: DENY and Content-Security-Policy: frame-ancestors 'none' security headers across all response paths.

Without these headers, an attacker could embed the Mesh admin UI inside a malicious page using an <iframe>, tricking authenticated users into performing unintended actions (e.g., modifying workspace settings, managing MCP servers, or changing access controls) by overlaying invisible frames on top of deceptive UI elements.

The fix applies headers at three layers to ensure full coverage:

• Hono middleware (apps/mesh/src/api/app.ts) — covers all API and server-rendered responses
• Bun.serve fetch handler (apps/mesh/src/index.ts) — wraps static asset responses that bypass Hono's middleware pipeline via handleAssets
• Asset server (packages/runtime/src/asset-server/index.ts) — adds headers directly to index.html cache-control responses so the entrypoint HTML is always protected

How to Test

1. Start the Mesh locally with bun run dev
2. Open browser DevTools → Network tab, load http://localhost:3000
3. Verify that responses (HTML page, API calls) include both X-Frame-Options: DENY and Content-Security-Policy: frame-ancestors 'none'
4. Create a test HTML file that attempts to embed the Mesh UI in an iframe: <iframe src="http://localhost:3000"></iframe> — the browser should refuse to render it
5. Confirm the application functions normally (no broken pages or blocked resources)

---

Summary by cubic

Mitigates UI redressing (clickjacking) in the Mesh admin by sending deny‑framing headers on all responses. Blocks iframe embedding to protect authenticated actions.

• Bug Fixes
  • Add X-Frame-Options: DENY and Content-Security-Policy: frame-ancestors 'none' via Hono middleware for API and server-rendered responses.
  • Wrap static asset responses from handleAssets with the same headers in apps/mesh/src/index.ts.

^{Written for commit c94d214. Summary will update on new commits.}

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Release Options

Should a new version be published when this PR is merged?

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Reaction	Type	Next Version
👍	Prerelease	2.165.2-alpha.1
🎉	Patch	2.165.2
❤️	Minor	2.166.0
🚀	Major	3.0.0

Current version: 2.165.1

Deployment

• Deploy to production (triggers ArgoCD sync after Docker image is published)

[cubic-dev-ai]

No issues found across 3 files

[cubic-dev-ai]

1 issue found across 1 file (changes from recent commits).

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="packages/runtime/src/asset-server/index.ts">

<violation number="1">
P1: Shared asset server stopped sending anti-clickjacking headers on HTML responses, weakening default protection for `createAssetHandler()` consumers.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P1: Shared asset server stopped sending anti-clickjacking headers on HTML responses, weakening default protection for createAssetHandler() consumers.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At packages/runtime/src/asset-server/index.ts, line 19:

<comment>Shared asset server stopped sending anti-clickjacking headers on HTML responses, weakening default protection for `createAssetHandler()` consumers.</comment>

<file context>
@@ -10,17 +10,13 @@ import { resolve, dirname, join, extname, basename, sep } from "path";
 ): Record<string, string> {
   if (filePath === indexPath || basename(filePath) === "index.html") {
-    return { "Cache-Control": "no-cache", ...SECURITY_HEADERS };
+    return { "Cache-Control": "no-cache" };
   }
 
</file context>