Is CVE-2026-49859 in the CISA KEV catalog?

No. CVE-2026-49859 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-49859?

CVE-2026-49859 has a CVSS v3 base score of 5.2 (MEDIUM).

What is the EPSS score for CVE-2026-49859?

CVE-2026-49859 has an EPSS score of 0.10% (1th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-49859?

Upgrade Deno to 2.8.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-49859

MEDIUM

5.2

CVSS v3

NVD

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.

CWE-693Protection Mechanism Failure CWE-918Server-Side Request Forgery (SSRF)

How to fix

Remediation Available

DenoWindows application

Affected:2.8.1Fixed in:2.8.1Deno Land Inc.

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Exploit Intelligence

0.10%probability of exploitation in 30 days

1stpercentile

Low risk: more likely to be exploited than 1% of all known CVEs.

References

Vendor Advisory1

github.com

Embed a live status badge for CVE-2026-49859

Markdown

[![CVE-2026-49859](https://tridentstack.com/cve/badge/CVE-2026-49859.svg)](https://tridentstack.com/cve/CVE-2026-49859)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-49859"><img src="https://tridentstack.com/cve/badge/CVE-2026-49859.svg" alt="CVE-2026-49859"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-29.