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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-33994 Detail

Description

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-B 6.3 MEDIUM
Vector:  CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4 GitHub, Inc.
https://github.com/locutusjs/locutus/pull/597 GitHub, Inc.
https://github.com/locutusjs/locutus/releases/tag/v3.0.25 GitHub, Inc.
https://github.com/locutusjs/locutus/security/advisories/GHSA-vc8f-x9pp-wf5p GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-1321 Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-33994
NVD Published Date:
03/27/2026
NVD Last Modified:
03/27/2026
Source:
GitHub, Inc.