CVE-2026-49859 — Deno: `fetch()` API sandbox bypass via missing DNS resolution check

CVE-2026-49859

Deno: `fetch()` API sandbox bypass via missing DNS resolution check PUBLISHED

Description (CNA)

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when fetch() was called, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially crafted domain name that passes the hostname check yet resolves to a denied IP, bypassing the network restriction entirely. This vulnerability is fixed in 2.8.1.

Affected (CNA)

Vendor / product	Versions
denoland / deno	affected < 2.8.1

CWE

CWE-693, CWE-918

References

https://github.com/denoland/deno/security/advisories/GHSA-cpgj-f7g3-2pp2

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.