CVE-2026-35356 is a medium-severity (CVSS 6.3) CWE-367 vulnerability in uu_install. A fix is available for uu_install — see the affected versions and patch details below.
uutils coreutils install Arbitrary File Overwrite with -D via Path Component Symlink Race
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-35356.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-35356 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 382,574 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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
The -D path runs fs::create_dir_all on a pathname then later opens the destination via path-based File::create/fs::copy, neither anchored to a directory fd. Between the two, an attacker can replace a path component with a symlink, redirecting the write.
Impact: an attacker with concurrent write access to the destination tree can redirect a privileged install -D to an arbitrary location, enabling arbitrary file overwrite with attacker-controlled content. Recommendation: use dirfd-based traversal (openat/mkdirat + O_NOFOLLOW) per component and create the destination via openat on the same dirfd.
Remediation: Acknowledged by Canonical; fixed in commit 0c412999.
Reported by Zellic in the uutils coreutils Program Security Assessment (prepared for Canonical, Jan 20 2026), audited commit 3a07ffc5a9bd4c283e75afa548ba1f1957bad242. Finding 3.51. Credit: Zellic.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | uu_install | all versions | 0.7.0cargo update -p uu_install --precise 0.7.0 |
Affected Products
coreutilsuutilsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for uu_install, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update uu_install to 0.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35356 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.
Frequently Asked Questions
Is CVE-2026-35356 in your dependencies?
Find it across crates.io, including transitive dependencies.