CVE-2026-35603: Claude Code: Insecure System-Wide Configuration Loading Enables Local Privilege Escalation on Windows
Claude Code is an agentic coding tool. In versions prior to 2.1.75 on Windows, Claude Code loaded the system-wide default configuration from C:\ProgramData\ClaudeCode\managed-settings.json without validating directory ownership or access permissions. Because the ProgramData directory is writable by non-administrative users by default and the ClaudeCode subdirectory was not pre-created or access-restricted, a low-privileged local user could create this directory and place a malicious configuration file that would be automatically loaded for any user launching Claude Code on the same machine. Exploiting this would have required a shared multi-user Windows system and a victim user to launch Claude Code after the malicious configuration was placed. This issue has been fixed on version 2.1.75.
Other sources
On Windows, Claude Code loaded system-wide default configuration from C:\ProgramData\ClaudeCode\managed-settings.json without validating directory ownership or access permissions. Because the ProgramData directory is writable by non-administrative users by default and the ClaudeCode subdirectory was not pre-created or access-restricted, a low-privileged local user could create this directory and place a malicious configuration file that would be automatically loaded for any user launching Claude Code on the same machine. Exploiting this would have required a shared multi-user Windows system and a victim user to launch Claude Code after the malicious configuration was placed.
Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version.
Thank you to hackerone.com/edbr for reporting this issue.
— GitHub
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-35603?
CVE-2026-35603 has been classified as high severity due to its potential for local privilege escalation.
How do I fix CVE-2026-35603?
To remediate CVE-2026-35603, upgrade Claude Code to version 2.1.75 or later.
Which versions of Claude Code are affected by CVE-2026-35603?
CVE-2026-35603 affects all versions of Claude Code prior to 2.1.75.
What is the risk associated with CVE-2026-35603?
The risk associated with CVE-2026-35603 includes unauthorized access and the ability to execute arbitrary code with elevated privileges.
Is there a workaround for CVE-2026-35603 before upgrading?
A potential workaround for CVE-2026-35603 is to restrict access to the C:\ProgramData\ClaudeCode\managed-settings.json file until the software can be updated.