An untrusted input to the `test_dispatcher` workflow in MeltanoHub allows command injection, enabling an attacker to inject arbitrary commands executed within the action environment. The injected commands can read and exfiltrate the repository’s GITHUB_TOKEN with write permissions, potentially granting full control over the repository, including the ability to push malicious commits and modify project configuration. The weakness is reflected in CWE‑1336 (Insecure Handling of Privileged Data) and CWE‑77 (Command Injection).

All versions of the MeltanoHub GitHub repository prior to commit 923820de8f64d753951fbbd54f7282a3d5f75173 are affected. The repository, hosted at hub.meltano.com, contains the vulnerable `test_dispatcher` workflow that leverages pull_request_target to run in the base repository context with access to secrets.

The CVSS score while an EPSS score of less than 1% suggests low current exploitation probability. The vulnerability is not currently listed in CISA’s KEV catalog. Exploitation requires an attacker to trigger the vulnerable workflow, most likely by submitting or modifying a pull request that targets the base repository. Successful exploitation grants the attacker the ability to execute arbitrary commands within the workflow runner.