A vulnerability has been identified in armeria-xds versions 1.38.0 through 1.39.0, where DataSourceStream in the xDS module can resolve control-plane-supplied filenames and environment variables without restriction, allowing a compromised or semi-trusted xDS control plane to read arbitrary local files and environment variables on the xDS client host.

Affected: Maven: com.linecorp.armeria:armeria-xds

## External Control of File Name or Path in xDS SDS DataSource

### Summary

`DataSourceStream` in the `:xds` module resolves control-plane-supplied `filename` and `environment_variable` fields from SDS Secret resources without any allow-list or base-directory confinement. A semi-trusted or compromised xDS control plane (or an attacker who can MITM SDS responses) can read arbitrary local files and environment variables on the xDS client host.

**Affected component:** `xds/src/main/java/com/linecorp/armeria/xds/DataSourceStream.java` **Introduced in:** Armeria 1.38.0 (commit `b199560b10`, "Add support for SDS", #6597) **Affected versions:** 1.38.0, 1.39.0

### Impact

A semi-trusted or compromised xDS control plane (or an attacker who can inject/MITM SDS responses) can:

- **Read arbitrary files** on the xDS client host — TLS private keys, `/etc/passwd`, mounted Kubernetes service-account tokens, cloud credential files, etc. - **Read arbitrary environment variables** — `AWS_SECRET_ACCESS_KEY`, CI tokens, database credentials, etc.

The read bytes are consumed as TLS key/cert/CA material. Combined with CWE-295 (silent disabling of upstream TLS peer verification), the exfiltrated secret can be presented to an attacker-chosen upstream, enabling data exfiltration. This is a confused-deputy / information-disclosure primitive driven entirely by control-plane-supplied configuration.

**Severity:** High — arbitrary host-level file and environment variable read via control-plane-pushe…