CVE-2026-49859
5.2 · MEDIUMOverview
CVE-2026-49859 is a medium-severity vulnerability affecting deno deno. It was published on June 23, 2026 and has a CVSS 3.1 base score of 5.2 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.2, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from deno. Update deno to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| deno | deno | >= 0, < 2.8.1 | Affected |
Frequently Asked Questions
What is CVE-2026-49859?
CVE-2026-49859 is a medium-severity vulnerability affecting deno deno. It was published on June 23, 2026 and has a CVSS 3.1 base score of 5.2 (MEDIUM).
How severe is CVE-2026-49859?
This vulnerability has a CVSS 3.1 base score of 5.2, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-49859?
Check the references section for vendor advisories and patches from deno. Update deno to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-49859?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-49859 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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