{"id":"CVE-2026-35355","aliases":["GHSA-239g-2685-54x3"],"title":"install: TOCTOU symlink race (unlink-then-create without O_EXCL) allows arbitrary file overwrite","summary":"install: TOCTOU symlink race (unlink-then-create without O_EXCL) allows arbitrary file overwrite","severity":"medium","cvss":6.3,"cwe":["CWE-59","CWE-367"],"vendor":"uu_install","product":"uu_install","ecosystem":"rust","affected":["uu_install < 0.6.0"],"patched":["uu_install 0.6.0"],"published":"2026-07-06","updated":"2026-07-06","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-239g-2685-54x3","references":[{"url":"https://github.com/uutils/coreutils/security/advisories/GHSA-239g-2685-54x3"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-35355"},{"url":"https://github.com/uutils/coreutils/pull/10067"},{"url":"https://github.com/uutils/coreutils/commit/b5bbabc18a1121908848d836f869a4e98eb63886"},{"url":"https://github.com/uutils/coreutils/releases/tag/0.6.0"},{"url":"https://github.com/advisories/GHSA-239g-2685-54x3"}],"tags":["ghsa","rust"],"epss":0.00118,"epssPercentile":0.01936,"ingestedAt":"2026-07-06T20:46:12.689Z","slug":"CVE-2026-35355","body":"## Overview\n\n`copy_file` in `install/src/install.rs` removes the destination then recreates it by pathname via `File::create` / `fs::copy` without `O_EXCL`/`create_new`. Between the unlink and the recreate, a local attacker with write access to the destination directory can drop in a symlink and redirect the write.\n\n**Impact:** when `install` runs privileged into an attacker-writable directory (staging/build paths), the race allows redirecting writes to arbitrary files and overwriting sensitive system files (`/etc/passwd`, `/etc/shadow`). Recommendation: create atomically with `create_new`/`O_EXCL` and copy via the opened fd rather than reopening by path.\n\n**Remediation:** Acknowledged by Canonical; fixed in commit b5bbabc1.\n\n---\n_Reported by Zellic in the *uutils coreutils Program Security Assessment* (prepared for Canonical, Jan 20 2026), audited commit `3a07ffc5a9bd4c283e75afa548ba1f1957bad242`. Finding 3.50. Credit: Zellic._\n\n## Affected packages\n\n- `uu_install < 0.6.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `uu_install 0.6.0`","depth":"sunlit","depthScore":35,"depthScoreParts":{"impact":34.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}