CVE-2026-49859
Deno: `fetch()` API sandbox bypass via missing DNS resolution check
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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
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
References (1)
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CVSS
- Attack Vector
- LOCAL
- Complexity
- LOW
- Privileges
- LOW
- User Interaction
- NONE
- Scope
- CHANGED
- Confidentiality
- LOW
- Integrity
- LOW
- Availability
- NONE
Quick Info
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