{"cve":"CVE-2026-25521","nvd":{"published":"2026-02-04T22:15:59.203","modified":"2026-07-15T02:18:53.903","status":"Modified","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.","cvss_v4":{"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","score":9.4},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":8.8},"cwes":["CWE-1321","CWE-915"],"references":["https://github.com/locutusjs/locutus/commit/042af9ca7fde2ff599120783e720a17f335bb01c","https://github.com/locutusjs/locutus/security/advisories/GHSA-rxrv-835q-v5mh","https://access.redhat.com/security/cve/CVE-2026-25521","https://bugzilla.redhat.com/show_bug.cgi?id=2436950","https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25521.json"],"products":["locutus:locutus"],"source":"nvd","synced_at":"2026-10-19T22:22:27.261130201+00:00"},"epss":{"cve":"CVE-2026-25521","score":0.00314,"percentile":0.24399,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-rxrv-835q-v5mh","url":"https://osv.dev/vulnerability/GHSA-rxrv-835q-v5mh","summary":"locutus is vulnerable to Prototype Pollution","modified":"2026-10-05T15:45:04.416035427Z","packages":[{"ecosystem":"npm","name":"locutus","purl":"pkg:npm/locutus","ranges":[">=2.0.12 <2.0.39"],"fixed":["2.0.39"]}]}],"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."]}