{"id":"GHSA-r3r9-wp5j-pq5g","summary":"request-filtering-agent: Synchronous throw from createConnection() for literal private-IP hosts bypasses req.on('error'), crashing the Node.js process","details":"### Summary\n`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.\n\n### Affected\n`request-filtering-agent` \u003c= 3.2.0 (latest).\n\n### PoC (replicated live on 3.2.0)\n```js\nconst http = require('http');\nconst { RequestFilteringHttpAgent } = require('request-filtering-agent');\nconst agent = new RequestFilteringHttpAgent();\nprocess.on('uncaughtException', e =\u003e {\n  console.log('CRASH:', e.message); // fires — process dies\n});\nconst req = http.get({ hostname: '169.254.169.254', port: 80, agent });\nreq.on('error', e =\u003e { /* never reached for literal IPs */ });\n```\nActual output:\n```\nrequest-filtering-agent@3.2.0 synchronous throw escaping error event:\nUNCAUGHT EXCEPTION (process crash): DNS lookup 169.254.169.254(...) is not allowed. Because, It is private IP address.\n*** CRASH CONFIRMED: createConnection throws sync, bypasses req.on(\"error\") ***\n```\nNote: 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.\n\n### Impact\nAny 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.\n\n### Fix\nInstead of throwing synchronously in `createConnection()`, call `callback(error)` (the Node.js `net.createConnection` error-callback convention) or use `process.nextTick(() =\u003e socket.destroy(error))` on the returned socket to emit the error asynchronously, allowing `req.on('error')` to handle it.","aliases":["CVE-2026-62985"],"modified":"2026-09-22T20:00:05.170933615Z","published":"2026-09-22T19:54:18Z","database_specific":{"github_reviewed_at":"2026-09-22T19:54:18Z","nvd_published_at":null,"cwe_ids":["CWE-248"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/azu/request-filtering-agent/security/advisories/GHSA-r3r9-wp5j-pq5g"},{"type":"WEB","url":"https://github.com/azu/request-filtering-agent/commit/9d12561064524807fc399158eaa5bd7a40dd8cd0"},{"type":"PACKAGE","url":"https://github.com/azu/request-filtering-agent"},{"type":"WEB","url":"https://github.com/azu/request-filtering-agent/releases/tag/v3.2.1"}],"affected":[{"package":{"name":"request-filtering-agent","ecosystem":"npm","purl":"pkg:npm/request-filtering-agent"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.2.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-r3r9-wp5j-pq5g/GHSA-r3r9-wp5j-pq5g.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}