# CVE-2026-123310: JetBrains IntelliJ IDEA Kotlin script arbitrary repository downloads

Source: https://junglewise.ai/threats/cve-2026-123310-in-jetbrains-intellij-idea-before-2026-3-kotlin-scripts-could  
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-2026-123310 · Severity: medium · CVSS 5.4 · Published 2026-11-06

JetBrains IntelliJ IDEA is a code editor used by developers. When opening an untrusted Kotlin script project, the editor could be tricked into downloading dependencies from arbitrary repositories controlled by an attacker, potentially delivering malicious code to a developer's machine.

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

## Quick answers

**Is CVE-2026-123310 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123310 being exploited in the wild.

**How severe is CVE-2026-123310?** Medium severity, with a CVSS score of 5.4, published 6 November 2026.

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

**Is there a fix for CVE-2026-123310?** 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-2026-123310 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-123310?** 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

IntelliJ IDEA's Kotlin script handling allows untrusted projects to specify arbitrary repository sources for dependency resolution. An attacker can craft a malicious Kotlin script that, when opened in the IDE without prior sandboxing or verification, triggers downloads from attacker-controlled repositories. This requires user interaction (opening the project) but could deliver supply-chain compromises.

## Affected products

- JetBrains IntelliJ IDEA 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

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- [JetBrains IntelliJ IDEA blind SSRF in JSON Schema validation](https://junglewise.ai/threats/cve-2026-123846-in-jetbrains-intellij-idea-before-2026-3-blind-ssrf-was-possible)