Summary
request-filtering-agent: Synchronous throw from createConnection() for literal private-IP hosts bypasses req.on('error'), crashing the Node.js process
RequestFilteringHttpAgent / RequestFilteringHttpsAgent block requests to private IPs, but the blocking happens via a synchronous throw inside createConnection() for literal private-IP hostnames (e.g. 169.254.169.254, 127.0.0.1). Node.js's http.request / http.get expects createConnection to emit an error asynchronously; a synchronous throw instead escapes the caller's req.on('error', ...) handler entirely and becomes an unhandled exception that crashes the process.
Affected
request-filtering-agent <= 3.2.0 (latest).
PoC (replicated live on 3.2.0)
const http = require('http');
const { RequestFilteringHttpAgent } = require('request-filtering-agent');
const agent = new RequestFilteringHttpAgent();
process.on('uncaughtException', e => {
console.log('CRASH:', e.message); // fires, process dies
});
const req = http.get({ hostname: '169.254.169.254', port: 80, agent });
req.on('error', e => { /* never reached for literal IPs */ });
Actual output:
[email protected] synchronous throw escaping error event:
UNCAUGHT EXCEPTION (process crash): DNS lookup 169.254.169.254(...) is not allowed. Because, It is private IP address.
*** CRASH CONFIRMED: createConnection throws sync, bypasses req.on("error") ***
Note: hostnames that resolve to private IPs (e.g. localhost) are handled via the async lookup path and correctly emit an error event, this asymmetry confirms the sync-throw is a defect.
Impact
Any application using request-filtering-agent where an attacker can trigger an HTTP request to a literal private-IP (e.g. from a user-supplied URL that is pre-validated but still reaches http.get) will crash the Node.js process, full DoS.
CVE-2026-62985 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.2.1); upgrading removes the vulnerable code path.
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.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Instead of throwing synchronously in createConnection(), call callback(error) (the Node.js net.createConnection error-callback convention) or use process.nextTick(() => socket.destroy(error)) on the returned socket to emit the error asynchronously, allowing req.on('error') to handle it.
Frequently Asked Questions
- What is CVE-2026-62985? CVE-2026-62985 is a high-severity security vulnerability in request-filtering-agent (npm), affecting versions < 3.2.1. It is fixed in 3.2.1.
- How severe is CVE-2026-62985? CVE-2026-62985 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of request-filtering-agent are affected by CVE-2026-62985? request-filtering-agent (npm) versions < 3.2.1 is affected.
- Is there a fix for CVE-2026-62985? Yes. CVE-2026-62985 is fixed in 3.2.1. Upgrade to this version or later.
- Is CVE-2026-62985 exploitable, and should I be worried? Whether CVE-2026-62985 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-2026-62985 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-2026-62985? Upgrade
request-filtering-agentto 3.2.1 or later.