# CVE-2025-62410 — capricorn86 happy-dom

> As of 2025-10-15, CVE-2025-62410 is a Critical-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in capricorn86 happy-dom, CVSS v4.0 9.4, EPSS 0.3% (26.9th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2025-62410, most recently “happy-dom sandbox escape RCE: CVE-2025-61927 (VM escape) and CVE-2025-62410 (prototype pollution)”.

**Last updated:** 2025-10-15

## What is CVE-2025-62410?

In versions before 20.0.2, it was found that --disallow-code-generation-from-strings is not sufficient for isolating untrusted JavaScript in happy-dom. The untrusted script and the rest of the application still run in the same Isolate/process, so attackers can deploy prototype pollution payloads to hijack important references like "process" in the example below, or to hijack control flow via flipping checks of undefined property. This vulnerability is due to an incomplete fix for CVE-2025-61927. The vulnerability is fixed in 20.0.2.

The record classifies CVE-2025-62410 under weakness class [CWE-1321](https://intel.threadlinqs.com/cwe/CWE-1321). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 362 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 9.4 — Critical (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 26.9% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 7.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2025-10-15

## Is CVE-2025-62410 being exploited?

Weaponised exploit code for CVE-2025-62410 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 20 in the Threadlinqs vulnerability feed.

- [trickest/cve](https://github.com/trickest/cve/blob/main/2025/CVE-2025-62410.md) (trickest)

## Affected products and versions

- **capricorn86**: happy-dom

Affected software packages:

- `npm:happy-dom` — patched in 20.0.2

## How to fix CVE-2025-62410

Fixed versions are recorded for 1 package: npm:happy-dom 20.0.2. No vendor patch reference has been recorded for CVE-2025-62410 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-2025-62410

1 tracked threat in the Threadlinqs corpus references CVE-2025-62410, 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-qpm2-6cq5-7pq5)

**Other references**

- [github.com](https://github.com/capricorn86/happy-dom/commit/f4bd4ebe3fe5abd2be2bcea1c07043c8b0b70eea)

Canonical: https://intel.threadlinqs.com/cve/CVE-2025-62410
Full detection coverage and IOCs for threats exploiting CVE-2025-62410 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp