fix(ci): prevent shell injection in GitHub Actions workflow#37
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Fix potential shell injection vulnerability in CI/CD workflow by avoiding GitHub expression interpolation.
## Changes
- Removed `env:` block that used `${{ github.head_ref || github.ref_name }}` interpolation
- Changed git push command to use GitHub's built-in environment variables (`GITHUB_HEAD_REF` and `GITHUB_REF_NAME`) directly in the shell
- Properly quoted the variable to prevent word splitting
## Why
Using `${{ }}` expression interpolation with `github.head_ref` in a workflow step can be exploited by attackers who create pull requests with maliciously crafted branch names. By using the shell environment variables `GITHUB_HEAD_REF` and `GITHUB_REF_NAME` (which GitHub Actions automatically provides), we avoid the expression interpolation while maintaining the same functionality. The shell handles these variables safely when properly quoted.
## Semgrep Finding Details
Using variable interpolation `${{...}}` with `github` context data in a `run:` step could allow an attacker to inject their own code into the runner. This would allow them to steal secrets and code. `github` context data can have arbitrary user input and should be treated as untrusted. Instead, use an intermediate environment variable with `env:` to store the data and use the environment variable in the `run:` script. Be sure to use double-quotes the environment variable, like this: "$ENVVAR".
Semgrep Assistant generated this pull request to fix [a finding](https://semgrep.dev/orgs/justmatias/findings/756619268) from the detection rule [yaml.github-actions.security.run-shell-injection.run-shell-injection](https://semgrep.dev/r/yaml.github-actions.security.run-shell-injection.run-shell-injection).
justmatias
approved these changes
Apr 18, 2026
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Fix potential shell injection vulnerability in CI/CD workflow by avoiding GitHub expression interpolation.
Changes
env:block that used${{ github.head_ref || github.ref_name }}interpolationGITHUB_HEAD_REFandGITHUB_REF_NAME) directly in the shellWhy
Using
${{ }}expression interpolation withgithub.head_refin a workflow step can be exploited by attackers who create pull requests with maliciously crafted branch names. By using the shell environment variablesGITHUB_HEAD_REFandGITHUB_REF_NAME(which GitHub Actions automatically provides), we avoid the expression interpolation while maintaining the same functionality. The shell handles these variables safely when properly quoted.Semgrep Finding Details
Using variable interpolation
${{...}}withgithubcontext data in arun:step could allow an attacker to inject their own code into the runner. This would allow them to steal secrets and code.githubcontext data can have arbitrary user input and should be treated as untrusted. Instead, use an intermediate environment variable withenv:to store the data and use the environment variable in therun:script. Be sure to use double-quotes the environment variable, like this: "$ENVVAR".Semgrep Assistant generated this pull request to fix a finding from the detection rule yaml.github-actions.security.run-shell-injection.run-shell-injection.