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