request-filtering-agent: Synchronous throw from createConnection() for literal private-IP hosts bypasses req.on('error'), crashing the Node.js process

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request-filtering-agent is an http(s).Agent implementation that blocks requests to Private/Reserved IP addresses. Prior to 3.2.1, RequestFilteringHttpAgent and RequestFilteringHttpsAgent synchronously threw from createConnection when rejecting a literal private-IP host such as 169.254.169.254 or 127.0.0.1. Because Node.js http.request and http.get expect connection failures to be delivered asynchronously, the throw bypassed req.on('error') and became an uncaught exception that could terminate the application process. Hostnames resolved through the asynchronous lookup path were not affected by this error-delivery asymmetry. This issue is fixed in version 3.2.1.

Source published

22 Sep 2026 19:13:19 UTC

Source modified

26 Sep 2026 00:08:11 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

request-filtering-agent is an http(s).Agent implementation that blocks requests to Private/Reserved IP addresses. Prior to 3.2.1, RequestFilteringHttpAgent and RequestFilteringHttpsAgent synchronously threw from createConnection when rejecting a literal private-IP host such as 169.254.169.254 or 127.0.0.1. Because Node.js http.request and http.get expect connection failures to be delivered asynchronously, the throw bypassed req.on('error') and became an uncaught exception that could terminate the application process. Hostnames resolved through the asynchronous lookup path were not affected by this error-delivery asymmetry. This issue is fixed in version 3.2.1.

Source published

Sep 22, 2026, 7:13:19 PM (timezone not stated)

Source modified

Sep 26, 2026, 12:08:11 AM (timezone not stated)

Observed here

11 Nov 2026 15:05:28 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

request-filtering-agent is an http(s).Agent implementation that blocks requests to Private/Reserved IP addresses. Prior to 3.2.1, RequestFilteringHttpAgent and RequestFilteringHttpsAgent synchronously threw from createConnection when rejecting a literal private-IP host such as 169.254.169.254 or 127.0.0.1. Because Node.js http.request and http.get expect connection failures to be delivered asynchronously, the throw bypassed req.on('error') and became an uncaught exception that could terminate the application process. Hostnames resolved through the asynchronous lookup path were not affected by this error-delivery asymmetry. This issue is fixed in version 3.2.1.

Source published

22 Sep 2026 20:17:04 UTC

Source modified

26 Sep 2026 01:17:01 UTC

Observed here

25 Oct 2026 14:19:28 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

### Summary `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) ```js 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. ### Fix 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.

Source published

22 Sep 2026 19:54:18 UTC

Source modified

22 Sep 2026 20:00:05 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · HIGH