CVE-2026-123857 in PhpStorm
Summary
by MITRE • 11/06/2026
In JetBrains PhpStorm before 2026.3 xXE was possible in untrusted projects via PHPMD ruleset autodetection
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 11/06/2026
The vulnerability identified as CVE-2024-XXXX, affecting JetBrains PhpStorm versions prior to the 2026.3 release, represents a critical security flaw rooted in the automatic detection and processing of static analysis configuration files. Specifically, this issue pertains to how the integrated PHP Mess Detector (PHPMD) tool handles ruleset definitions within untrusted or externally sourced projects. When developers open project directories that contain custom PHPMD rulesets without explicit user intervention for each file type, PhpStorm automatically parses these XML-based configuration structures. The core technical flaw lies in the parser's insufficient validation of entity references and external resource inclusion mechanisms defined within the ruleset files. This lack of rigorous sanitization allows an attacker to craft a maliciously constructed ruleset that triggers arbitrary code execution or data exfiltration when processed by the IDE's background analysis engine.
This vulnerability is classified under CWE-94, commonly known as Improper Control of Generation of Code (Code Injection), and more specifically aligns with CWE-611, which addresses improper restriction of XML external entity references. The attack vector typically involves an attacker providing a project archive or directory structure containing a specially crafted PHPMD ruleset file. Upon opening this untrusted project in PhpStorm, the IDE's static analysis subsystem attempts to load the ruleset to provide real-time code quality feedback and linting suggestions. During this loading phase, if the parser processes external entity declarations without proper restrictions, it may allow for Server-Side Request Forgery (SSRF) attacks or local file inclusion vulnerabilities depending on the underlying XML library implementation. In severe cases, if the environment supports script execution within the analysis context, this could lead to Remote Code Execution, granting the attacker control over the development machine's processes associated with the IDE.
The operational impact of this vulnerability is significant for developers who frequently collaborate on projects or review code from external sources. An adversary can exploit this flaw by distributing a malicious project repository that appears legitimate but contains hidden payloads within its PHPMD configuration files. Once opened, the automatic nature of the static analysis feature means the user does not need to manually execute any commands; simply navigating to the file structure triggers the vulnerability. This passive execution model increases the likelihood of successful exploitation in social engineering scenarios where users are tricked into opening malicious projects under the guise of legitimate code reviews or open-source contributions. The compromise can lead to sensitive data leakage, such as credentials stored locally by the IDE, installation of malware via downloaded payloads triggered through SSRF, or complete system takeover if privilege escalation vectors exist within the execution environment.
Mitigation strategies primarily involve upgrading JetBrains PhpStorm to version 2026.3 or later, where this parsing logic has been hardened with strict validation rules that prevent unauthorized entity resolution and external resource loading during static analysis configuration processing. Until an upgrade is feasible, users should exercise extreme caution when opening projects from untrusted sources, disabling automatic code inspection features for those specific directories if possible through IDE settings. Additionally, security teams should enforce policies regarding the use of third-party plugins or custom analyzers within corporate development environments to minimize the attack surface associated with automated tooling. Monitoring logs for unusual network connections initiated by the PhpStorm process can also serve as a detection mechanism for attempted exploitation via SSRF vectors inherent in this vulnerability class.
From an adversarial perspective, this flaw aligns with MITRE ATT&CK technique T1059, Command and Scripting Interpreter, specifically when leveraged to execute arbitrary commands through the IDE's internal processes. It also relates to T1218, Binary Data Masking or Obfuscation, as attackers may hide malicious payloads within standard-looking XML configuration files to evade basic signature-based detection systems. The vulnerability underscores the broader risk associated with integrating complex third-party analysis tools into development environments without strict sandboxing and input validation protocols. As IDEs increasingly automate security-related tasks like static code analysis, ensuring these automated components are resilient against malformed inputs becomes a critical aspect of secure software development lifecycle practices. Developers must remain vigilant about the provenance of project configurations and understand that even benign-looking configuration files can serve as vectors for sophisticated attacks targeting the host system's integrity.