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CVE PROGRAM SOURCE RECORD5.2 Medium

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

denoland deno

  • < 2.8.1affected

References