A vulnerability in the Gemini CLI and its associated GitHub Action allowed an unprivileged attacker to invoke arbitrary code execution by providing untrusted local .env files that overwrite the GEMINI_CLI_HOME environment variable. The flaw arises from insufficient validation of environment variable content, enabling malicious code to be executed under the permissions of the CI job. The attacker gains the same privileges as the workflow, potentially compromising the build environment or downstream deploys.

The affected products are Google Cloud Gemini CLI and the Google Cloud Run Gemini CLI GitHub Action. Versions prior to the latest release (v0.1.22) are impacted, as the advisory does not list a specific vulnerability fix date but recommends upgrading to the latest version. Users should verify that their installed Gemini CLI or action matches or exceeds the released version on GitHub.

The CVSS score of 9.2 indicates a high severity of potential impact. EPSS is not available, and the vulnerability is not currently listed in CISA KEV. The likely attack vector involves an attacker with write access to a repository or the ability to supply local .env files in the CI environment, then executing arbitrary commands as the job's runner. Based on the description, the vulnerability appears exploitable via the CI workflow and requires untrusted local data; prevention is through updating to a patched version and configuring GEMINI_TRUST_WORKSPACE as directed by the vendor.