GHSA-239g-2685-54x3 is a medium-severity (CVSS 6.3) CWE-367 vulnerability in uu_install. O3 Security confirms whether GHSA-239g-2685-54x3 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
install: TOCTOU symlink race (unlink-then-create without O_EXCL) allows arbitrary file overwrite
Real-World Exposure
uu_installReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
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.
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.
Remediation: Acknowledged by Canonical; fixed in commit b5bbabc1.
Reported by Zellic in the uutils coreutils Program Security Assessment (prepared for Canonical, Jan 20 2026), audited commit 3a07ffc5a9bd4c283e75afa548ba1f1957bad242. Finding 3.50. Credit: Zellic.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | uu_install | all versions | 0.6.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for uu_install. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update uu_install to 0.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-239g-2685-54x3 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-239g-2685-54x3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-239g-2685-54x3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-239g-2685-54x3 in your dependencies?
O3 detects GHSA-239g-2685-54x3 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.