CVE-2026-49859
Deno: `fetch()` API sandbox bypass via missing DNS resolution check
Description
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.
INFO
Published Date :
June 23, 2026, 5:14 p.m.
Last Modified :
June 23, 2026, 5:14 p.m.
Remotely Exploit :
No
Source :
GitHub_M
Affected Products
The following products are affected by CVE-2026-49859
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update Deno to version 2.8.1 or later.
- Ensure all network access controls are properly configured.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-49859 vulnerability anywhere in the article.