CVE-2026-31975

CVE-2026-31975 is an OS command injection vulnerability (CWE-78) affecting Cloud CLI, also known as Claude Code UI, a desktop and mobile user interface for tools including Claude Code, Cursor CLI, Codex, and Gemini-CLI. In versions prior to 1.25.0, the server/index.js component directly interpolates unsanitized user inputs—specifically projectPath and initialCommand from WebSocket message payloads—into bash command strings, enabling arbitrary OS command execution. A secondary injection vector exists through the unsanitized sessionId. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity.

The vulnerability can be exploited remotely by unauthenticated attackers with network access to the affected application, requiring low complexity and no user interaction. By crafting malicious WebSocket messages, attackers can inject and execute arbitrary operating system commands on the host running the Cloud CLI server, potentially leading to full system compromise with high confidentiality, integrity, and availability impacts.

Mitigation is available in version 1.25.0, which addresses the injection flaws through proper input sanitization. Security practitioners should update to this release immediately. Relevant resources include the fixing commit at https://github.com/siteboon/claudecodeui/commit/12e7f074d9563b3264caf9cec6e1b701c301af26, the release page at https://github.com/siteboon/claudecodeui/releases/tag/v1.25.0, and the GitHub security advisory at https://github.com/siteboon/claudecodeui/security/advisories/GHSA-gv8f-wpm2-m5wr.