CVE-2026-49859
Medium · 5.2CVSS
5.2
EPSS
0.1%
Published
Jun 23, 2026
CISA due date
—
The record
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 packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| crates.io | deno | 0 | 2.8.1 |
Related vulnerabilities
- GHSA-cpgj-f7g3-2pp2 Deno: `fetch()` API sandbox bypass via missing DNS resolution check Same vulnerability
- CVE-2026-55517 Deno is a JavaScript, TypeScript, and WebAssembly runtime. Also affects deno
- CVE-2026-49860 Deno is a JavaScript, TypeScript, and WebAssembly runtime. Also affects deno
- CVE-2026-49983 Deno is a JavaScript, TypeScript, and WebAssembly runtime. Also affects deno
- CVE-2026-49401 Deno is a JavaScript, TypeScript, and WebAssembly runtime. Also affects deno
- CVE-2026-49411 Deno is a JavaScript, TypeScript, and WebAssembly runtime. Also affects deno
- CVE-2026-49402 Deno is a JavaScript, TypeScript, and WebAssembly runtime. Also affects deno
- CVE-2026-49440 Deno is a JavaScript, TypeScript, and WebAssembly runtime. Also affects deno