CVE-2017-17458
CRITICALCVE-2017-17458 is a critical-severity (CVSS 9.8) OS Command Injection vulnerability in mercurial. O3 Security confirms whether CVE-2017-17458 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Mercurial vulnerable to arbitrary code injection
Blast Radius
mercurialReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
In Mercurial before 4.4.1, it is possible that a specially malformed repository can cause Git subrepositories to run arbitrary code in the form of a .git/hooks/post-update script checked into the repository. Typical use of Mercurial prevents construction of such repositories, but they can be created programmatically.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | mercurial | all versions | 4.4.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mercurial. 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 mercurial to 4.4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-17458 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-2017-17458 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-2017-17458. 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-2017-17458 in your dependencies?
O3 detects CVE-2017-17458 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.