CVE-2018-1285
CRITICALCVE-2018-1285 is a critical-severity (CVSS 9.8) XML External Entity (XXE) vulnerability in log4net. O3 Security confirms whether CVE-2018-1285 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
XML External Entity attack in log4net
Real-World Exposure
log4netReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Apache log4net versions before 2.0.10 do not disable XML external entities when parsing log4net configuration files. This allows for XXE-based attacks in applications that accept attacker-controlled log4net configuration files.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | log4net | all versions | 2.0.10 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for log4net. 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 log4net to 2.0.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1285 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-2018-1285 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-2018-1285. 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-2018-1285 in your dependencies?
O3 detects CVE-2018-1285 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.