Report: CVE-2026-33993 - Locutus has Prototype Pollution via __proto__ Key Injection in unserialize()
CVE ID :CVE-2026-33993 Published : March 27, 2026, 11:17 p.m. | 37 minutes ago 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. Severity: 6.9 | MEDIUM Visit the link for more details, such as CVSS details, affected products, timeline, and more...