Steeltoe: TLS private keys written to /tmp with default permissions, never deleted

### Summary 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`. ### Impact Any process co-located in the container that runs as a different UID can read the TLS client private key from `/tmp` and use it to impersonate the application when connecting to the backing database over mutual TLS. ### Affected configuration - Application is deployed on Cloud Foundry or another environment that populates `VCAP_SERVICES` with a MySQL or PostgreSQL service binding that includes `sslKey` credentials. - A process running as a different UID shares the container's filesystem. ### Mitigations If an immediate upgrade is not possible, prevent other processes from running in the container under a different UID with access to `/tmp`.

Source published

2 Jul 2026 20:32:09 UTC

Source modified

2 Jul 2026 20:56:33 UTC

Observed here

23 Oct 2026 16:01:25 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Publisher rating · MODERATE