Steeltoe: TLS private keys written to /tmp with default permissions, never deleted
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-312.
Summary
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`.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| SteeltoeOSS | Steeltoe.Configuration.Abstractions | 4.0.0 to before 4.2.0 | 4.2.0 | Patch available | CNA |
| — | Steeltoe.Configuration.Abstractions (NuGet) | 4.0.0 to before 4.2.0 | 4.2.0 | Patch available | GHSA-rxrh-4j9h-xgg9 |
- Steeltoe.Configuration.Abstractions VendorSteeltoeOSS Affected 4.0.0 to before 4.2.0 Fixed in 4.2.0 Patch available CNA
- Steeltoe.Configuration.Abstractions (NuGet) Vendor— Affected 4.0.0 to before 4.2.0 Fixed in 4.2.0 Patch available GHSA-rxrh-4j9h-xgg9
Remediation
- Fix · CNA Steeltoe.Configuration.Abstractions (SteeltoeOSS) Fixed in 4.2.0
- Fix · GHSA-rxrh-4j9h-xgg9 Steeltoe.Configuration.Abstractions (NuGet) Fixed in 4.2.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-50267
- 2026-10-03 Alias added: GHSA-rxrh-4j9h-xgg9
References
More SteeltoeOSS vulnerabilities
- TI-2024-27048 Basic Auth Credential Leakage to Logs After Fetch Registry Error in Steeltoe.Discovery.Eureka with Peer Awareness CVSS 3.1MEDIUM 5.3
- TI-2026-36953 Steeltoe vulnerable to management-port isolation bypass via spoofed Host header CVSS 3.1HIGH 8.2
- TI-2026-56238 Steeltoe.Discovery.Consul: malformed 'secure' metadata aborts service instance lookup (DoS) CVSS 3.1HIGH 7.5
- TI-2026-56237 Steeltoe.Discovery.Eureka: malformed enum/bool/timestamp field aborts entire registry fetch (DoS) CVSS 3.1HIGH 7.5
- TI-2026-36955 Steeltoe.Discovery.Eureka: Unrecognized DataCenterInfo.Name poisons entire registry fetch CVSS 3.1HIGH 7.5
- TI-2026-36959 Steeltoe's env sanitizer misses connection strings — leaks embedded DB passwords CVSS 3.1HIGH 7.5
Sources
- CVE-2026-50267 · CVE Program
- CVE-2026-50267 · NVD
- FIRST EPSS
- GHSA-rxrh-4j9h-xgg9 · GitHub Advisory Database · CC BY 4.0
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