CVE-2026-35603
Claude Code: Insecure System-Wide Configuration Loading Enables Local Privilege Escalation on Windows
Description
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.
How to fix CVE-2026-35603
To remediate CVE-2026-35603, upgrade the affected package to a fixed version below.
- —upgrade to 2.1.75 or later
Is CVE-2026-35603 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 2.1.75
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | HIGH7.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H |