Description

In JetBrains IntelliJ IDEA before 2026.3 kotlin scripts could trigger dependency downloads from arbitrary repositories in untrusted projects

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.4",
  "pubDate": "2026-11-06T11:17:10.193Z",
  "pubdate": "2026-11-06T11:17:10.193Z",
  "executiveSummary": "A security vulnerability exists within JetBrains IntelliJ IDEA concerning the handling of Kotlin scripts in untrusted projects. The flaw allows for unauthorized dependency downloads from arbitrary, potentially malicious, remote repositories.\nThis vulnerability is classified as an improper input validation issue that bypasses intended security controls for package resolution. By manipulating the configuration of Kotlin scripts, an attacker can coerce the IDE into fetching external artifacts from attacker-controlled servers.\nThe primary risk involves supply chain compromise and arbitrary code execution potential if malicious dependencies are resolved and subsequently executed or utilized by the IDE's build/execution environment. This vulnerability affects IntelliJ IDEA versions prior to 2026.3.\nExploitation requires a victim to open or import a maliciously crafted project. An attacker with the ability to provide a project file to a developer can leverage this flaw to intercept development workflows, perform repository poisoning, or conduct man-in-the-middle attacks against the dependency resolution process.\nThe vulnerability highlights a significant risk for users opening projects from untrusted sources, as the environment fails to sufficiently restrict the resolution logic for Kotlin-based dependencies, potentially leading to unauthorized data exfiltration or system compromise.",
  "technicalDetails": "The vulnerability resides in the Kotlin script evaluation and dependency resolution subsystem within IntelliJ IDEA. In versions prior to 2026.3, the IDE's handling of script configurations (typically defined in .kts files) fails to validate or restrict the origins of remote repositories when dependencies are declared.\nThe root cause is an insufficient sandbox or configuration policy enforcement during the script interpretation phase. When an IntelliJ IDEA project is loaded, the IDE attempts to resolve dependencies defined in Kotlin scripts. Because the IDE does not strictly enforce a whitelist of trusted repositories or validate the integrity of the dependency metadata, it blindly follows instructions provided within the project script files to connect to external endpoints.\nThe exploitation flow typically begins with an attacker preparing a malicious project containing a crafted Kotlin script. This script defines a repository block pointing to an attacker-controlled server hosting malicious artifacts. When the victim opens this project in a vulnerable version of IntelliJ IDEA, the IDE's dependency management engine initiates a network request to the specified arbitrary repository.\nBy redirecting the resolution process, an attacker can facilitate the download of malicious binaries or libraries that mimic legitimate dependencies. If the IDE or the build process integrates these downloaded artifacts into the execution path, it can lead to remote code execution (RCE) on the developer's machine.\nFurthermore, the vulnerability allows for the leaking of environmental data during the connection request, as the IDE may transmit identifying headers or authentication tokens if a misconfigured internal repository is targeted. The lack of validation on the repository source effectively bypasses the trust boundaries that the IDE is expected to maintain for project-level configurations.\nThe attack is persistent within the project scope; once the malicious script is parsed, the IDE attempts to reach out to the remote server automatically. There is no requirement for high-level privileges; the vulnerability operates within the context of the user account running the IDE. This mechanism demonstrates a failure in the secure-by-default design required for handling arbitrary project scripts, as the environment does not isolate the dependency resolution process from the user's host system security context."
}