CVE-2026-123369

### Impact The GitHub Actions runner treats certain text in a step's output as commands. The legacy form, `##[command]`, is recognized anywhere in a line. compose-lint's text report prints service names, environment keys and lines of the Compose file, and it does not neutralize `##[`. Inside the compose-lint Action, a Compose file from a pull request can therefore: - create fake error or warning annotations on the pull request (`##[error]`, `##[warning]`) - fold the rest of the log, including the real verdict, out of sight (`##[group]`) - blank out chosen strings for the rest of the log (`##[add-mask]`) GitHub has postponed removing the deprecated `set-output` log command, so the runner still honors it. A test run of the Action on a GitHub-hosted runner confirmed that a `::set-output` line from a Compose file is processed. Whether it can override the Action's own `sarif-written` output, which decides whether the SARIF upload step runs, has not been tested. The exit code and the pass/fail result are not affected. Azure Pipelines parses the same `##[` syntax, so the pip package is listed for anyone printing the text report in other CI systems. Found during an internal pre-1.0 security review. ### Patches Fixed in 0.31.0. The Action stops the runner from processing workflow commands while compose-lint's output is printed, using a random `stop-commands` token. The text report also escapes `##[`, and `::` at the start of a line, in anything taken from the Compose file. ### Workarounds - In your own workflow, wrap the compose-lint step in `::stop-commands::<random token>` and `::<random token>::`. - Use `--format json` or `--format sarif` rather than the text report when linting untrusted pull requests. ### Reproduction ```yaml services: web: image: "nginx:1.25" environment: "##[error]DB_PASSWORD": placeholder "##[group]svc": image: "nginx:1.25" privileged: true ``` Run through the Action, this produces a fake error annotation and fol