{"id":"CVE-2026-25521","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-25521","generatedAt":"2026-10-28T00:17:04.558Z","title":"In versions from 2.0.12 to before 2.0.39, a prototype pollution vulnerability exists in locutus.","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.","published":"2026-02-04T22:15:59.000Z","lastModified":"2026-07-15T02:18:54.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":9.4,"severity":"CRITICAL","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-1321","CWE-915"],"affected":["locutus/locutus"],"epss":{"score":0.00319,"percentile":0.24665,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.32%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/locutusjs/locutus/commit/042af9ca7fde2ff599120783e720a17f335bb01c","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/locutusjs/locutus/security/advisories/GHSA-rxrv-835q-v5mh","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://access.redhat.com/security/cve/CVE-2026-25521","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2436950","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25521.json","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-25521","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}