{"id":"CVE-2026-33994","aliases":["GHSA-vc8f-x9pp-wf5p"],"url":"https://o3.security/vulnerability/CVE-2026-33994","summary":"Locutus Prototype Pollution due to incomplete fix for CVE-2026-25521","details":"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.","published":"2026-03-27T22:15:47.131Z","modified":"2026-07-15T01:49:00.708355660Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"locutus","fixedVersion":"3.0.25"}],"fix":{"url":"https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4","label":"locutusjs/locutus@345a621"},"references":[{"type":"WEB","url":"https://github.com/locutusjs/locutus/releases/tag/v3.0.25"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33994.json"},{"type":"ADVISORY","url":"https://github.com/locutusjs/locutus/security/advisories/GHSA-vc8f-x9pp-wf5p"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33994"},{"type":"FIX","url":"https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4"},{"type":"FIX","url":"https://github.com/locutusjs/locutus/pull/597"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:00.708355660Z"}}