Deno: Node TCPWrap numeric hostname aliases bypass --deny-net resolved-IP deny checks

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-49411: 0.16% estimated exploitation activity in the next 30 days; percentile 4.94 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Deno's network permission model is designed so that --deny-net rules apply to the resolved IP address of a destination, not just the literal string supplied by the caller. That means --deny-net=127.0.0.1 (or --deny-net=127.0.0.0/8) is expected to block any attempt to reach loopback, regardless of how the hostname is spelled. On affected versions, the Node.js compatibility TCP path checked the permission against the original hostname string before resolution and then did not re-check after resolution. A caller could therefore pass a numeric alias of an IP address (for example the decimal integer 2130706433 or the hex form 0x7f000001, both of which resolve to 127.0.0.1) and reach the denied destination through node:net.connect or node:http.request's { host, port } options form. The native Deno.connect(), fetch(), and URL-string variants of node:http.request("http://...") were not affected, because they either re-checked permissions after resolution or normalized the hostname…

Published by the source

16 Jun 2026, 19:09 UTC

Last modified by the source

20 Jul 2026, 21:01 UTC

Source last checked

26 Oct 2026, 15:43 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-v8fw-85r8-5m23

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# Patch Next advisory brief: CVE-2026-49411

Advisory: Deno: Node TCPWrap numeric hostname aliases bypass --deny-net resolved-IP deny checks
IDs: CVE-2026-49411, GHSA-v8fw-85r8-5m23
Record: https://patchnext.com/advisories/cve-2026-49411 (revision 1, source checked 26 Oct 2026, 15:43 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: deno 2.8.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io deno: affected <= 2.7.14; fixed in 2.8.0

## Suggested inspection (read-only)
- crates.io deno: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on deno.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-v8fw-85r8-5m23 (GitHub-reviewed advisory GHSA-v8fw-85r8-5m23 lists affected ranges: crates.io deno >=0 <=2.7.14)

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