{"schema":"threatline.record/2","record":{"id":"CVE-2026-103435","aliases":["GHSA-5j29-h97v-84ch"],"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.\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.","categories":["Unclassified"],"product":"@anthropic-ai/claude-code","vendor":"Anthropic","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-103435","source_modified_at":"2026-10-07T14:39:13.225Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"@anthropic-ai/claude-code","vendor":"Anthropic","versions":[{"lessThan":"2.1.129","status":"affected","version":"0","versionType":"semver"}],"defaultStatus":null},{"source":"GitHub Advisory Database","source_url":"https://github.com/anthropics/claude-code/security/advisories/GHSA-5j29-h97v-84ch","source_modified_at":"2026-10-05T12:45:33Z","fetched_at":"2026-10-23T21:14:28.314422Z","package":{"ecosystem":"npm","name":"@anthropic-ai/claude-code"},"range":"< 2.1.129"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-103435","source_modified_at":"2026-10-07T14:39:13.225Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"@anthropic-ai/claude-code","ecosystem":null},"version":"2.1.129","basis":"first unaffected version stated in the CVE record"},{"source":"GitHub Advisory Database","source_url":"https://github.com/anthropics/claude-code/security/advisories/GHSA-5j29-h97v-84ch","source_modified_at":"2026-10-05T12:45:33Z","fetched_at":"2026-10-23T21:14:28.314422Z","package":{"ecosystem":"npm","name":"@anthropic-ai/claude-code"},"version":"2.1.129"}],"cvss":7.7,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00251,"percentile":0.15547,"score_date":"2026-10-23"},"published_at":"2026-10-07T12:50:02.572Z","modified_at":"2026-10-07T14:39:13.225Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-103435","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-07T14:39:13.225Z"},{"source":"GitHub Advisory Database","url":"https://github.com/anthropics/claude-code/security/advisories/GHSA-5j29-h97v-84ch","fetched_at":"2026-10-23T21:14:28.314422Z","source_modified_at":"2026-10-05T12:45:33Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-103435","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","GitHub Advisory Database","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/anthropics/claude-code/security/advisories/GHSA-5j29-h97v-84ch"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"total","assessed_at":"2026-10-07T14:39:02.916533Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-07T14:39:13.225Z","content_hash":"c4460ac56379fd7dff8c15235c84a8aacac92643f94e38dd97f0d0570321fd48"}}