CVE-2026-35370
MEDIUMCVE-2026-35370 is a medium-severity (CVSS 4.4) CWE-863 vulnerability in uu_id. O3 Security confirms whether CVE-2026-35370 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
id: groups= computed from real GID instead of effective GID
Real-World Exposure
uu_idReal-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 id utility in uutils coreutils miscalculates the groups= section of its output. The implementation uses a user's real GID instead of their effective GID to compute the group list, leading to potentially divergent output compared to GNU coreutils. Because many scripts and automated processes rely on the output of id to make security-critical access-control or permission decisions, this discrepancy can lead to unauthorized access or security misconfigurations.
Zellic finding 3.72. Reported in the Zellic uutils coreutils Program Security Assessment (for Canonical, Jan 2026), audited commit 3a07ffc5a9bd4c283e75afa548ba1f1957bad242.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | uu_id | 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_id. 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_id to 0.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35370 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 CVE-2026-35370 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 CVE-2026-35370. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-35370 in your dependencies?
O3 detects CVE-2026-35370 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.