{"cve":"CVE-2026-33994","nvd":{"published":"2026-03-27T23:17:14.413","modified":"2026-10-26T22:10:00.163","status":"Modified","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.","cvss_v4":{"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","score":6.3},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-1321"],"references":["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"],"products":["locutus:locutus"],"source":"nvd","synced_at":"2026-10-26T22:26:44.656832877+00:00"},"epss":{"cve":"CVE-2026-33994","score":0.00568,"percentile":0.46809,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-vc8f-x9pp-wf5p","url":"https://osv.dev/vulnerability/GHSA-vc8f-x9pp-wf5p","summary":"Locutus Prototype Pollution due to incomplete fix for CVE-2026-25521","modified":"2026-03-30T20:34:57.635752Z","packages":[{"ecosystem":"npm","name":"locutus","purl":"pkg:npm/locutus","ranges":[">=2.0.39 <3.0.25"],"fixed":["3.0.25"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}