CVE-2026-33993

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.

• CWE-1321

• https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4Patch
• https://github.com/locutusjs/locutus/pull/597Issue Tracking
• https://github.com/locutusjs/locutus/releases/tag/v3.0.25Release Notes
• https://github.com/locutusjs/locutus/security/advisories/GHSA-4mph-v827-f877Exploit, Mitigation, Vendor Advisory

Published

Mar 27, 2026

Last Modified

Jun 17, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-33987FreeRDP is a free implementation of the Remote Desktop Proto…6.6
• CVE-2026-33989Mobile Next is an MCP server for mobile development and auto…6.5
• CVE-2026-3399A vulnerability was identified in Tenda F453 1.0.0.3. Affect…8.8
• CVE-2026-33990Docker Model Runner (DMR) is software used to manage, run, a…9.1
• CVE-2026-33991WeGIA is a web manager for charitable institutions. Prior to…8.8
• CVE-2026-33992pyLoad is a free and open-source download manager written in…6.5
• CVE-2026-33994Locutus brings stdlibs of other programming languages to Jav…9.8
• CVE-2026-33995FreeRDP is a free implementation of the Remote Desktop Proto…5.3
• CVE-2026-33996LibJWT is a C JSON Web Token Library. Starting in version 3.…5.5
• CVE-2026-33997Moby is an open source container framework. Prior to version…8.1
• CVE-2026-33999A flaw was found in the X.Org X server. This integer underfl…7.8
• CVE-2026-3400A security flaw has been discovered in Tenda AC15 up to 15.1…9.8