What’s Vulnerable › Vulnerabilities

CVE-2025-62410: --disallow-code-generation-from-strings is not sufficient for isolating untrusted JavaScript in happy-dom

• Severity: critical (CVSS 9.4 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-10-15 · updated 2026-10-08
• Weakness: CWE-1321

Description

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.

Affected products

• capricorn86 happy-dom: before 20.0.2

References

• https://github.com/capricorn86/happy-dom/commit/f4bd4ebe3fe5abd2be2bcea1c07043c8b0b70eea
• https://github.com/capricorn86/happy-dom/security/advisories/GHSA-qpm2-6cq5-7pq5

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