{"id":"CVE-2026-103435","revision":"58ba05d152bb4161ae2e8c15ab3bbd69","records":[{"revision":"58ba05d152bb4161ae2e8c15ab3bbd69","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-103435","aliases":[],"title":"Arbitrary File Write via Write-Time Symlink Following (TOCTOU) in Claude Code","description":"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.\n\nUsers on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version.\n\nThank you to hackerone.com/c_h4ck_0 for reporting this issue.","state":0,"publishedAt":"2026-10-07T12:50:02.572+00:00","modifiedAt":"2026-10-07T14:39:13.225+00:00","affected":[{"ecosystem":"Vendor product","name":"@anthropic-ai/claude-code","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Anthropic\",\n                    \"product\": \"@anthropic-ai/claude-code\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.1.129\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"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","score":7.7,"severity":"HIGH"}],"references":["https://github.com/anthropics/claude-code/security/advisories/GHSA-5j29-h97v-84ch"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-103435","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-103435","identifiers":["CVE-2026-103435"]},"retained":false,"historicalAffected":[]}],"coverage":[]}