CVE-2026-49411: Deno Node TCPWrap numeric hostname aliases bypass --deny-net resolved-IP deny checks

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-23 · updated 2026-10-25
Weakness: CWE-284

Description

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.0, 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. This vulnerability is fixed in 2.8.0.

Affected products

denoland deno: from 2.7.14 before 2.8.0 — fixed in 2.8.0

How to fix

Upgrade to a fixed version: denoland deno 2.8.0. Check the vendor advisory for mitigations.

References

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