{"cve":"CVE-2026-33993","nvd":{"published":"2026-03-27T23:17:14.237","modified":"2026-10-26T21:10:00.170","status":"Analyzed","description":"Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Prior to version 3.0.25, the `unserialize()` function in `locutus/php/var/unserialize` assigns deserialized keys to plain objects via bracket notation without filtering the `__proto__` key. When a PHP serialized payload contains `__proto__` as an array or object key, JavaScript's `__proto__` setter is invoked, replacing the deserialized object's prototype with attacker-controlled content. This enables property injection, for...in propagation of injected properties, and denial of service via built-in method override. This is distinct from the previously reported prototype pollution in `parse_str` (GHSA-f98m-q3hr-p5wq, GHSA-rxrv-835q-v5mh) — `unserialize` is a different function with no mitigation applied. Version 3.0.25 patches the issue.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","score":6.9},"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-4mph-v827-f877"],"products":["locutus:locutus"],"source":"nvd","synced_at":"2026-10-26T21:38:48.864438205+00:00"},"epss":{"cve":"CVE-2026-33993","score":0.00592,"percentile":0.48018,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-4mph-v827-f877","url":"https://osv.dev/vulnerability/GHSA-4mph-v827-f877","summary":"Locutus has Prototype Pollution via __proto__ Key Injection in unserialize()","modified":"2026-03-30T20:34:55.046784Z","packages":[{"ecosystem":"npm","name":"locutus","purl":"pkg:npm/locutus","ranges":["<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."]}