CVE-2026-49860
Deno: WebSocket API sandbox bypass via missing post-DNS check
Description
Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when a WebSocket connection was opened, 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, 5:15 p.m.
Last Modified :
June 23, 2026, 5:15 p.m.
Remotely Exploit :
No
Source :
GitHub_M
Affected Products
The following products are affected by CVE-2026-49860
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.
- Review and enforce --deny-net rules for all network access.
- Validate IP addresses against network restrictions.
- Monitor network activity for suspicious connections.
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).
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CVE-2026-49860 vulnerability anywhere in the article.