Quick answers
- Is CVE-2026-123838 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-123838 being exploited in the wild.
- How severe is CVE-2026-123838?
- High severity, with a CVSS score of 7.8, published 6 November 2026.
- Which products and versions are affected?
- Jetbrains IntelliJ IDEA before 2026.3.
- Is there a fix for CVE-2026-123838?
- Yes: fixed in IntelliJ IDEA 2026.3 and later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-123838 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-123838?
- 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 and later
Technical details
The vulnerability exists in IntelliJ IDEA's UI Designer form file parser, which fails to properly validate or sandbox form files when the IDE operates in Safe Mode. An attacker can craft a malicious form file that, when opened or processed by the IDE, bypasses Safe Mode restrictions to achieve arbitrary code execution. This affects IntelliJ IDEA versions before 2026.3.
Affected products
- JetBrains IntelliJ IDEA before 2026.3
Timeline
- 2026-11-06: disclosed