CVE-2026-49859Deno: `fetch()` API sandbox bypass via missing DNS resolution check
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.2 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-693, CWE-918
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Analyzed
- Record last updated
- Jun 24, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.