CVE-2026-50267
MEDIUMSteeltoe: TLS private keys written to /tmp with default permissions, never deleted
Blast Radius
Steeltoe.Configuration.AbstractionsReal-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
Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. In Steeltoe.Configuration.Abstractions 4.0.0 through 4.1.0, when MySQL or PostgreSQL service bindings from VCAP_SERVICES include TLS client credentials, the Connectors library writes those credentials to temporary files in Path.GetTempPath() using File.CreateText. On Linux, File.CreateText creates files with mode 0644 (world-readable) under the process umask, and the files are never deleted. The same key material is protected at mode 0400 in /proc/<pid>/environ. Steeltoe.Configuration.Abstractions version 4.2.0 patches the issue. If an immediate upgrade is not possible, prevent other processes from running in the container under a different UID with access to /tmp.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Steeltoe.Configuration.Abstractions | ≥ 4.0.0&&< 4.2.0 | 4.2.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Steeltoe.Configuration.Abstractions. 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 Steeltoe.Configuration.Abstractions to 4.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50267 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-2026-50267 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-2026-50267. 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-2026-50267 in your dependencies?
O3 detects CVE-2026-50267 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.