# CVE-2026-123857: JetBrains PhpStorm XML external entity injection in PHPMD ruleset autodetection

Source: https://junglewise.ai/threats/cve-2026-123857-in-jetbrains-phpstorm-before-2026-3-xxe-was-possible-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-06. Updated: 2026-11-06  
License: CC BY 4.0 with a link back

CVE-2026-123857 · Severity: medium · CVSS 4.3 · Published 2026-11-06

JetBrains PhpStorm is an integrated development environment for PHP developers. When opening untrusted projects, PhpStorm automatically detects and loads PHPMD code quality rulesets, which can contain malicious XML that triggers external entity injection (XXE). An attacker could exploit this to read sensitive files or execute arbitrary code on a developer's machine.

Technologies: [Jetbrains PhpStorm](https://junglewise.ai/threats/technologies/phpstorm). Vendors: [Jetbrains](https://junglewise.ai/threats/vendors/jetbrains).

## Quick answers

**Is CVE-2026-123857 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123857 being exploited in the wild.

**How severe is CVE-2026-123857?** Medium severity, with a CVSS score of 4.3, published 6 November 2026.

**Which products and versions are affected?** Jetbrains PhpStorm before 2026.3.

**Is there a fix for CVE-2026-123857?** Yes: fixed in PhpStorm 2026.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-123857 attacked?** It is attacked with local access, in a web application.

**Am I affected by CVE-2026-123857?** Check whether you run Jetbrains PhpStorm at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in PhpStorm 2026.3

## Technical details

XXE vulnerability in PHPMD ruleset autodetection allows XML external entity injection when processing untrusted ruleset files. The vulnerability affects PhpStorm's automatic configuration detection in untrusted projects, where an attacker-controlled ruleset can be loaded without explicit user confirmation. Successful exploitation requires the developer to open a malicious project.

## Affected products

- JetBrains PhpStorm before 2026.3

## Timeline

- 2026-11-06: disclosed

## References

- [https://www.jetbrains.com/privacy-security/issues-fixed/](https://www.jetbrains.com/privacy-security/issues-fixed/)

## Related threats

- [JetBrains PhpStorm automatic project file upload to deployment server](https://junglewise.ai/threats/cve-2026-123858-in-jetbrains-phpstorm-before-2026-3-project-files-could-be)
- [JetBrains Toolbox App and IDEs compromised certificate trust](https://junglewise.ai/threats/cve-2026-118697-in-jetbrains-toolbox-app-before-3-9-1-and-3-8-2-intellij-idea)
- [JetBrains IDEs embedded browser trusted revoked certificates](https://junglewise.ai/threats/cve-2026-118696-in-jetbrains-intellij-idea-pycharm-phpstorm-rubymine-and)
- [JetBrains PhpStorm arbitrary code execution via configured interpreter](https://junglewise.ai/threats/cve-2026-64809-jetbrains-phpstorm-arbitrary-code-execution-via-configured)
- [JetBrains PhpStorm arbitrary code execution in project tooling](https://junglewise.ai/threats/cve-2026-64808-jetbrains-phpstorm-arbitrary-code-execution-in-project-tooling)