CVE-2026-25521
Locutus is vulnerable to Prototype Pollution
- State
- Published
- Severity
- 9.4 Critical
- Published
- Feb 4, 2026
- Updated
- Jul 15, 2026
- Reserved
- Feb 2, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.4 Critical | 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 | GitHub_M |
| 3.1 | 9.3 Critical | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H | redhat-SADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
locutuslocutusjs |
|
References
- https://github.com/locutusjs/locutus/security/advisories/GHSA-rxrv-835q-v5mh
- https://github.com/locutusjs/locutus/commit/042af9ca7fde2ff599120783e720a17f335bb01c
- https://access.redhat.com/security/cve/CVE-2026-25521vdb-entry
- RHBZ#2436950issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25521.json
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