{"id":"CVE-2026-33993","summary":"Locutus has Prototype Pollution via __proto__ Key Injection in unserialize()","details":"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.","aliases":["GHSA-4mph-v827-f877"],"modified":"2026-04-10T05:42:59.345358Z","published":"2026-03-27T22:14:03.495Z","database_specific":{"cna_assigner":"GitHub_M","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33993.json","cwe_ids":["CWE-1321"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33993.json"},{"type":"FIX","url":"https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4"},{"type":"FIX","url":"https://github.com/locutusjs/locutus/pull/597"},{"type":"WEB","url":"https://github.com/locutusjs/locutus/releases/tag/v3.0.25"},{"type":"ADVISORY","url":"https://github.com/locutusjs/locutus/security/advisories/GHSA-4mph-v827-f877"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33993"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/locutusjs/locutus","events":[{"introduced":"0"},{"fixed":"0d2402bdb92f9c59918114af9c8ba628f22e9152"}],"database_specific":{"versions":[{"introduced":"0"},{"fixed":"3.0.25"}]}}],"versions":["v1.3.2","v2.0.0","v2.0.1","v2.0.10","v2.0.11","v2.0.12","v2.0.13","v2.0.14","v2.0.15","v2.0.16","v2.0.17","v2.0.19","v2.0.2","v2.0.20","v2.0.21","v2.0.22","v2.0.23","v2.0.24","v2.0.25","v2.0.26","v2.0.27","v2.0.28","v2.0.29","v2.0.3","v2.0.30","v2.0.32","v2.0.33","v2.0.34","v2.0.35","v2.0.36","v2.0.37","v2.0.38","v2.0.39","v2.0.4","v2.0.5","v2.0.6","v2.0.7","v2.0.8","v2.0.9","v3.0.0","v3.0.1","v3.0.10","v3.0.11","v3.0.12","v3.0.13","v3.0.14","v3.0.15","v3.0.16","v3.0.17","v3.0.18","v3.0.19","v3.0.2","v3.0.20","v3.0.21","v3.0.22","v3.0.23","v3.0.24","v3.0.3","v3.0.4","v3.0.5","v3.0.6","v3.0.7","v3.0.8","v3.0.9"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33993.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"}]}