The vulnerability arises from improper trust boundary enforcement in Kiro IDE before version 0.8.0. Code running inside the IDE incorrectly accepts partially trusted project directory files, allowing a malicious actor to inject arbitrary code that is executed when a local user opens the directory. This flaw is mapped to CWE-829 and results in Remote Code Execution, potentially compromising confidentiality, integrity, and availability of the host system.

Affected systems include the AWS‑branded Kiro IDE on all supported platforms, specifically any release older than 0.8.0. The build changelog indicates that the fix was introduced in the 0.8.0 release, meaning all earlier versions are vulnerable regardless of platform.

The CVSS score of 8.5 indicates a high severity with an impact of arbitrary code execution. EPSS data is not available and the vulnerability is not listed in CISA’s KEV catalog. Because the flaw can be triggered by a local user who opens a crafted project directory, an unauthenticated remote attacker can deliver such a directory and cause the affected user to unwittingly execute code. No known exploits have been published yet, but the combination of high severity and an easily exploitable attack vector warrants immediate remediation.