GHSA-7rx4-c5vx-g8w3 Karakeep SDK has SSRF via metascraper-logo-favicon that bypasses validateUrl protections

• npm @karakeep/sdk: < 0.32.0 → fixed in 0.32.0

Summary The `metascraper-logo-favicon` plugin makes HTTP requests to URLs extracted from attacker-controlled HTML without going through the application's `validateUrl()` SSRF protections. This allows any authenticated user to make the server fetch arbitrary internal URLs by bookmarking a page containing a crafted `` tag. Details Protected path (correct) Karakeep implements comprehensive SSRF protections in `apps/workers/network.ts` (lines 12-222). The `validateUrl()` function blocks loopback, private, link-local, carrier-grade NAT, and reserved IP ranges. It resolves DNS before the fetch and checks all resolved IPs against the blacklist. This function is correctly used by `fetchWithProxy()` for the main bookmark URL fetch, image downloads, RSS feeds, and webhooks. Unprotected path (vulnerability) After fetching the page HTML (with SSRF protection), the content is passed to a parse subprocess (`apps/workers/scripts/parseHtmlSubprocess.ts`). Inside this subprocess, `metascraper-logo-favicon` (v5.49.5) extracts favicon URLs from the HTML DOM by matching `` elements and reading their `href` attribute. The plugin then calls `reachable-url` (which wraps `got`) to verify each extracted URL. These HTTP requests bypass `validateUrl()` entirely: ```typescript // apps/workers/scripts/parseHtmlSubprocess.ts, lines 62-73 metascraperLogo({ gotOpts: { agent: { http: serverConfig.proxy.httpProxy ? new HttpProxyAgent(getRandomProxy(serverConfig.proxy.httpProxy)) : undefined, https: serverConfig.proxy.httpsProxy ? new HttpsProxyAgent(getRandomProxy(serverConfig.proxy.httpsProxy)) : undefined, }, }, }), ``` Only proxy agent configuration is provided. No URL validation hooks, no IP blacklist, no DNS resolution checks. The `got` HTTP client makes direct requests to whatever URLs are extracted from the HTML. Data flow ``` 1. User creates bookmark → URL validated by validateUrl() ✓ 2. Page HTML fetched → via fetchWithProxy() with SSRF protection ✓ 3. HTML passed to parseHtmlSubprocess via stdin 4. metascraper-logo-favicon parses tags from HTML 5. Plugin calls reachable-url → got.get(faviconUrl) → NO validateUrl() ✗ 6. Server makes HTTP GET to attacker-controlled internal URL ``` Comparison The application explicitly protects the main URL fetch with `validateUrl()` (network.ts:136-222), which blocks all private/loopback IPs and resolves DNS before connecting. The recent commit history shows deliberate SSRF hardening ("Stricter SSRF validation" on 2025-11-02, allowlist feature on 2025-11-22). However, the metascraper plugins' internal HTTP requests are not routed through this validation. PoC 1. Set up a malicious page on a public URL ```html Innocent Page Normal content ``` 2. Create a bookmark via the API ```bash curl -X POST http://localhost:3000/api/v1/bookmarks \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{"type": "link", "url": "https://attacker.example.com/ssrf.html"}' ``` 3. Result The main URL (`https://attacker.example.com/ssrf.html`) passes `validateUrl()` since it resolves to a public IP. After the HTML is fetched, `metascraper-logo-favicon` extracts the favicon URLs and calls `reachable-url`/`got` to verify them. The server makes HTTP GET requests to: • `http://169.254.169.254/latest/meta-data/` (AWS IMDS) • `http://127.0.0.1:3000/api/v1/users/whoami` (localhost) • `http://192.168.1.1/admin` (internal network) These requests bypass all SSRF protections. Verification: Monitor outbound network traffic from the karakeep container or check the logo field in the bookmark response. Impact • Cloud metadata access: On AWS/GCP/Azure deployments, the server can be forced to fetch instance metadata (e.g., `http://169.254.169.254/latest/meta-data/iam/security-credentials/`) which may expose IAM credentials. • Internal service discovery: Attacker can probe internal network services and ports by checking whether the favicon URL was reachable. • Redirect-based data leak: If an internal service responds with a redirect, the final URL (potentially containing tokens or session data) is stored as the bookmark's logo field and visible to the attacker. • Bypass of explicit security controls: The application's SSRF protections (IP blacklist, DNS resolution, redirect validation) are rendered ineffective for this code path. Suggested Fix ```diff // apps/workers/scripts/parseHtmlSubprocess.ts + import { validateUrl } from "network"; + + // Create a got hook that validates URLs before requests + const ssrfHook = { + beforeRequest: [ + async (options) => { + const result = await validateUrl(options.url.toString(), false); + if (!result.ok) { + throw new Error(`SSRF blocked: ${result.reason}`); + } + } + ] + }; + metascraperLogo({ gotOpts: { + hooks: ssrfHook, agent: { ... }, }, }), ``` Alternatively, run the parse subprocess in a network-restricted sandbox (network namespace, nsjail, or a Docker container with restricted networking).