CVE-2026-103435 (GCVE-0-2026-103435)
Vulnerability from cvelistv5
Published
2026-10-07 12:50
Modified
2026-10-07 14:39
CWE
  • CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
  • CWE-61 - UNIX Symbolic Link (Symlink) Following
  • CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
Summary
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.
Impacted products
Show details on NVD website


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