CVE-2026-103435
Claude Code validated that a target file path resided within the project working directory at permission-check time, but re-resolved the path at write time without repeating that validation. This time-of-check to time-of-use (TOCTOU) gap allowed an attacker who could write to the workspace to atomically replace a project file with a symlink, causing Claude Code to follow the symlink and write its output to an arbitrary file outside the project sandbox. Exploitation required the ability to win a race condition against the write operation and write access to the shared workspace, enabling a lower-privileged attacker to redirect benign edits to sensitive files (e.g., shell configuration) in a higher-privileged session. 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/c_h4ck_0 for reporting this issue.
- Score
- CVSS 4.0 7.7 High
- Status
- Awaiting Analysis - 98a01053-8a31-4f6d-9aa9-252be161adc6
- Published
- 2026-10-07
- Last modified
- 2026-10-07
- Weaknesses
- CWE-22, CWE-367, CWE-61
Affected products
References
- https://github.com/anthropics/claude-code/security/advisories/GHSA-5j29-h97v-84ch
