CVE-2026-25521
High
Description
Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. In versions from 2.0.12 to before 2.0.39, a prototype pollution vulnerability exists in locutus. Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using String.prototype. This issue has been patched in version 2.0.39.
SeverityHigh
CVSS8.8
Exploit probability—
ProductLocutus
PublishedFeb 4, 2026
First seenFeb 4, 2026
Weakness typeCWE-1321Prototype pollution
How to fix
Update
- locutus locutus2.0.39 or later
- locutus2.0.39 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| locutus locutus | 2.0.12 ≤ v < 2.0.39 | 2.0.39 |
| locutusnpm | 2.0.12 ≤ v < 2.0.39 | 2.0.39 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
In the Intelligence 360 plan
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.