CVE-2026-26189

Command Injection in aquasecurity/trivy-action via Unsanitized Environment Variable Export A command injection vulnerability exists in `aquasecurity/trivy-action` due to improper handling of action inputs when exporting environment variables. The action writes `export VAR=<input>` lines to `trivy_envs.txt` based on user-supplied inputs and subsequently sources this file in `entrypoint.sh`. Because input values are written without appropriate shell escaping, attacker-controlled input containing shell metacharacters (e.g., `$(...)`, backticks, or other command substitution syntax) may be evaluated during the sourcing process. This can result in arbitrary command execution within the GitHub Actions runner context. **Severity:** Moderate CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N CWE-78: Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’) **Impact:** Successful exploitation may lead to arbitrary command execution in the CI runner environment. **Affected Versions:** * Versions >= 0.31.0 and <= 0.33.1 * Introduced in commit `7aca5ac` **Affected Conditions:** The vulnerability is exploitable when a consuming workflow passes attacker-controlled data into any action input that is written to `trivy_envs.txt`. Access to user input is required by the malicious actor. A representative exploitation pattern involves incorporating untrusted pull request metadata into an action parameter. For example: ```yaml - uses: aquasecurity/trivy-action@0.33.1 with: output: "trivy-${{ github.event.pull_request.title }}.sarif" ``` If the pull request title contains shell syntax, it may be executed when the generated environment file is sourced. **Not Affected:** * Workflows that do not pass attacker-controlled data into `trivy-action` inputs * Workflows that upgrade to a patched version that properly escapes shell values or eliminates the `source ./trivy_envs.txt` pattern * Workflows where user input is not accessible. **Call Sites:** * `action.yaml:188` — `set_env_var_if_provided` writes unescaped `export` lines * `entrypoint.sh:9` — sources `./trivy_envs.txt`