# CVE-2026-123311: JetBrains IntelliJ IDEA command execution in Markdown preview

Source: https://junglewise.ai/threats/cve-2026-123311-in-jetbrains-intellij-idea-before-2026-3-2026-2-4-command  
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-2026-123311 · Severity: medium · CVSS 5.3 · Published 2026-11-06

JetBrains IntelliJ IDEA is a development environment used by programmers to write and test software. A hidden control in the Markdown preview feature could allow an attacker to execute arbitrary commands on a developer's machine, potentially compromising their work, credentials, or system.

Technologies: [Jetbrains IntelliJ IDEA](https://junglewise.ai/threats/technologies/intellij-idea). Vendors: [Jetbrains](https://junglewise.ai/threats/vendors/jetbrains).

## Quick answers

**Is CVE-2026-123311 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123311 being exploited in the wild.

**How severe is CVE-2026-123311?** Medium severity, with a CVSS score of 5.3, published 6 November 2026.

**Which products and versions are affected?** Jetbrains IntelliJ IDEA before 2026.3, 2026.2.4.

**Is there a fix for CVE-2026-123311?** Yes: fixed in IntelliJ IDEA 2026.3, 2026.2.4. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-123311 attacked?** It is attacked with local access, in a web application.

**Am I affected by CVE-2026-123311?** Check whether you run Jetbrains IntelliJ IDEA 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 IntelliJ IDEA 2026.3, 2026.2.4

## Technical details

The vulnerability involves a hidden run control in the Markdown preview component of IntelliJ IDEA that fails to properly restrict command execution. An attacker could craft a malicious Markdown document that, when previewed, executes arbitrary commands with the privileges of the IDE process. This requires user interaction (opening a Markdown file) but no authentication.

## Affected products

- JetBrains IntelliJ IDEA before 2026.3, 2026.2.4

## Timeline

- 2026-11-06: disclosed

## References

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

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