How severe is CVE-2026-49859?

CVE-2026-49859 has a CVSS 3.x base score of 5.2, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-49859 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-49859?

CVE-2026-49859 affects Deno. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-49859?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-49859 have an EU (EUVD) identifier?

Yes. CVE-2026-49859 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38541.

When was CVE-2026-49859 published?

CVE-2026-49859 was published on 2026-06-23 and last updated on 2026-06-29.

CVE-2026-49859

CVE-2026-49859 is a medium-severity vulnerability in Deno with a CVSS 3.x base score of 5.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-693.

Key facts

Severity: Medium (CVSS 3.x base score 5.2)
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38541
Weakness: CWE-693
Affected product: Deno
Published: 2026-06-23
Last modified: 2026-06-29

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.

Frequently asked questions

What is CVE-2026-49859?: 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.
How severe is CVE-2026-49859?: CVE-2026-49859 has a CVSS 3.x base score of 5.2, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-49859 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-49859?: CVE-2026-49859 affects Deno. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-49859?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-49859 have an EU (EUVD) identifier?: Yes. CVE-2026-49859 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38541.
When was CVE-2026-49859 published?: CVE-2026-49859 was published on 2026-06-23 and last updated on 2026-06-29.

References

https://github.com/denoland/deno/security/advisories/GHSA-cpgj-f7g3-2pp2

Affected products (1)

cpe:2.3:a:deno:deno:*:*:*:*:*:*:*:*

More vulnerabilities in Deno

CVE-2022-24783 — Critical (CVSS 10.0): Deno is a runtime for JavaScript and TypeScript. The versions of Deno between release 1.18.0 and 1.20.2 (inclusive) are…
CVE-2023-28445 — Critical (CVSS 9.9): Deno is a runtime for JavaScript and TypeScript that uses V8 and is built in Rust. Resizable ArrayBuffers passed to…
CVE-2021-32619 — Critical (CVSS 9.8): Deno is a runtime for JavaScript and TypeScript that uses V8 and is built in Rust. In Deno versions 1.5.0 to 1.10.1,…
CVE-2025-48935 — Critical (CVSS 9.1): Deno is a JavaScript, TypeScript, and WebAssembly runtime. Starting in version 2.2.0 and prior to versions 2.2.5, it is…
CVE-2024-27936 — High (CVSS 8.8): Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. Starting in version 1.32.1 and prior to…
CVE-2023-28446 — High (CVSS 8.8): Deno is a simple, modern and secure runtime for JavaScript and TypeScript that uses V8 and is built in Rust. Arbitrary…

All CVEs affecting Deno →

Other CWE-693 (Protection Mechanism Failure) vulnerabilities

CVE-2026-47140 — Critical (CVSS 10.0): vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, NodeVM blocks several dangerous Node.js builtins…
CVE-2026-34208 — Critical (CVSS 10.0): SandboxJS is a JavaScript sandboxing library. Prior to 0.8.36, SandboxJS blocks direct assignment to global objects…
CVE-2026-34938 — Critical (CVSS 10.0): PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs…
CVE-2026-2761 — Critical (CVSS 10.0): Sandbox escape in the Graphics: WebRender component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33,…
CVE-2022-32845 — Critical (CVSS 10.0): This issue was addressed with improved checks. This issue is fixed in watchOS 8.7, iOS 15.6 and iPadOS 15.6, macOS…
CVE-2026-45102 — Critical (CVSS 9.9): OneUptime is an open-source monitoring and observability platform. Prior to 10.0.98, OneUptime uses the Node.js' vm…

Browse all CWE-693 (Protection Mechanism Failure) vulnerabilities →