Command Injection vulnerability in the JavaDoc hover provider of the vscode-java extension

Summary

A flaw was found in the vscode-java extension, which provides Java language support for Visual Studio Code. The extension incorrectly trusts all Markdown content in JavaDoc hovers, allowing a malicious Java file to include hidden commands. If a user clicks a specially crafted link within a JavaDoc hover popup, an attacker can execute arbitrary VS Code commands, which can lead to full system compromise in trusted workspaces. A flaw was found in the vscode-java extension, which provides Java language support for Visual Studio Code. The extension incorrectly trusts all Markdown content in JavaDoc hovers, allowing a malicious Java file to include hidden commands. If a user clicks a specially crafted link within a JavaDoc hover popup, an attacker can execute arbitrary VS Code commands, which can lead to full system compromise in trusted workspaces. The Red Hat Product Security team has assessed the severity of this vulnerability as Important, given that it requires a user to open a malicious Java source file and interact with a hover popup. Successful exploitation allows an attacker to execute arbitrary commands within the context of the VS Code editor and potentially the underlying operating system. The vulnerability's root cause is the over-trusting of Markdown content returned by the Java language server, which fails to isolate extension-generated trusted links from attacker-controlled JavaDoc content. Red Hat severity: Important — CVSS 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). Weakness: CWE-88. No fixing RHSA erratum has published yet; monitor the Red Hat CVE page and patch when it ships.