CVE-2026-103435
- Source
- https://cve.org/CVERecord?id=CVE-2026-103435
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-103435.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-103435
- Aliases
-
- GHSA-5j29-h97v-84ch
- Published
- 2026-10-07T12:50:02Z
- Modified
- 2026-10-08T02:49:15Z
- Severity
-
- 7.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N CVSS Calculator
- Summary
- Arbitrary File Write via Write-Time Symlink Following (TOCTOU) in Claude Code
- Details
-
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.
- Database specific
{ "cna_assigner": "Anthropic", "cwe_ids": [ "CWE-22", "CWE-367", "CWE-61" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/103xxx/CVE-2026-103435.json" }- References