CVE-2026-33994

Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Starting in version 2.0.39 and prior to version 3.0.25, a prototype pollution vulnerability exists in the `parse_str` function of the npm package locutus. An attacker can pollute `Object.prototype` by overriding `RegExp.prototype.test` and then passing a crafted query string to `parse_str`, bypassing the prototype pollution guard. This vulnerability stems from an incomplete fix for CVE-2026-25521. The CVE-2026-25521 patch replaced the `String.prototype.includes()`-based guard with a `RegExp.prototype.test()`-based guard. However, `RegExp.prototype.test` is itself a writable prototype method that can be overridden, making the new guard bypassable in the same way as the original — trading one hijackable built-in for another. Version 3.0.25 contains an updated fix.

CVSS

No CVSS.

References

Link	Resource
https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4
https://github.com/locutusjs/locutus/pull/597
https://github.com/locutusjs/locutus/releases/tag/v3.0.25
https://github.com/locutusjs/locutus/security/advisories/GHSA-vc8f-x9pp-wf5p
https://github.com/locutusjs/locutus/security/advisories/GHSA-vc8f-x9pp-wf5p

Configurations

No configuration.

History

No history.

Information

Published : 2026-03-27 23:17

Updated : 2026-03-30 13:26

NVD link : CVE-2026-33994

Mitre link : CVE-2026-33994

CVE.ORG link : CVE-2026-33994

JSON object : View

Products Affected

No product.

CWE

CWE-1321

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

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