CVE-2026-70375: HashBrown CMS: OS Command Injection via Git Deployer Branch Field

HashBrown CMS through 1.4.6 contains an OS Command Injection vulnerability (CWE-78) in the Git deployer component. GitDeployer.pullRepo() in src/Server/Entity/Deployer/GitDeployer.js executes AppService.exec(git checkout ${this.branch || 'master'}), interpolating the configured branch value directly into a shell command with no escaping. GitDeployer.validate() only rejects a single-quote character in the repo, branch, username, and password fields; shell metacharacters such as ';', '&&', '|', backticks, and '$()' are not filtered. A user able to configure a project's Git deployer settings can set a malicious branch value (e.g. 'master;<command>#') that executes automatically on every subsequent deployer operation (media upload, content save, etc.), since pullRepo() is invoked unconditionally at the start of each such operation. This is related to CVE-2020-6948, which addressed single-quote escaping of the repo, username, and password fields in the same file's git clone invocation; the branch field used in the unquoted git checkout command was not covered by that fix and remains injectable.