# CVE-2025-61927 — capricorn86 happy-dom

> As of 2025-10-10, CVE-2025-61927 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in capricorn86 happy-dom, CVSS v4.0 7.2, EPSS 0.6% (49.3th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2025-61927, most recently “happy-dom sandbox escape RCE: CVE-2025-61927 (VM escape) and CVE-2025-62410 (prototype pollution)”.

**Last updated:** 2025-10-10

## What is CVE-2025-61927?

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Happy DOM v19 and lower contains a security vulnerability that puts the owner system at the risk of RCE (Remote Code Execution) attacks. A Node.js VM Context is not an isolated environment, and if the user runs untrusted JavaScript code within the Happy DOM VM Context, it may escape the VM and get access to process level functionality. It seems like what the attacker can get control over depends on if the process is using ESM or CommonJS. With CommonJS the attacker can get hold of the `require()` function to import modules. Happy DOM has JavaScript evaluation enabled by default. This may not be obvious to the consumer of Happy DOM and can potentially put the user at risk if untrusted code is executed within the environment. Version 20.0.0 patches the issue by changing JavaScript evaluation to be disabled by default.

The record classifies CVE-2025-61927 under weakness class [CWE-94](https://intel.threadlinqs.com/cwe/CWE-94). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 367 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 7.2 — High (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:A/VC:L/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **EPSS (FIRST):** 0.6% probability of exploitation in the next 30 days, higher than 49.3% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 7.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2025-10-10

## Is CVE-2025-61927 being exploited?

Weaponised exploit code for CVE-2025-61927 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 25 in the Threadlinqs vulnerability feed.

- [trickest/cve](https://github.com/trickest/cve/blob/main/2025/CVE-2025-61927.md) (trickest)

## Affected products and versions

- **capricorn86**: happy-dom

Affected software packages:

- `npm:happy-dom` — patched in 20.0.0

## How to fix CVE-2025-61927

Fixed versions are recorded for 1 package: npm:happy-dom 20.0.0. No vendor patch reference has been recorded for CVE-2025-61927 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2025-61927

1 tracked threat in the Threadlinqs corpus references CVE-2025-61927, either in the campaign’s CVE list or as an indicator on the campaign record.

- [happy-dom sandbox escape RCE: CVE-2025-61927 (VM escape) and CVE-2025-62410 (prototype pollution)](https://intel.threadlinqs.com/threat/TL-2026-3367) — CRITICAL · 2026-10-12

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-12. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com](https://github.com/capricorn86/happy-dom/security/advisories/GHSA-37j7-fg3j-429f)

**Other references**

- [github.com](https://github.com/capricorn86/happy-dom/commit/819d15ba289495439eda8be360d92a614ce22405)

Canonical: https://intel.threadlinqs.com/cve/CVE-2025-61927
Full detection coverage and IOCs for threats exploiting CVE-2025-61927 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp