CVE-2025-54416 is a critical command injection vulnerability affecting the tj-actions/branch-names GitHub Action workflow versions prior to 9.0.0. This GitHub Action is designed to retrieve branch or tag names across various events in CI/CD pipelines. The vulnerability arises from improper neutralization of special elements (CWE-77) in branch or tag names, which are used as inputs without adequate sanitization or escaping in the action's output. Although some internal sanitization exists, the output remains vulnerable, allowing attackers to craft malicious branch or tag names that inject arbitrary commands into downstream workflows. This can lead to arbitrary command execution within the context of the GitHub Actions runner, potentially compromising the CI/CD environment and any connected resources. The CVSS v3.1 score of 9.1 reflects the high severity, with network attack vector, low attack complexity, requiring low privileges but no user interaction, and a scope change indicating that the vulnerability affects resources beyond the initially vulnerable component. The impact includes high confidentiality loss, low integrity loss, and low availability loss. No known exploits are reported in the wild yet, but the critical nature and ease of exploitation make it a significant threat to organizations using this action in their pipelines. The issue was addressed in version 9.0.0 of the tj-actions/branch-names repository, which properly sanitizes and escapes outputs to prevent command injection.

For European organizations leveraging GitHub Actions in their software development lifecycle, this vulnerability poses a substantial risk. Exploitation can lead to unauthorized command execution within CI/CD runners, potentially exposing sensitive source code, credentials, or deployment secrets. This can result in data breaches, supply chain compromises, or unauthorized deployment of malicious code. Given the widespread adoption of GitHub Actions among European enterprises, especially in technology, finance, and critical infrastructure sectors, the vulnerability could disrupt development workflows and undermine trust in automated pipelines. Additionally, compromised CI/CD environments could be used as pivot points for lateral movement within corporate networks, increasing the risk of broader organizational compromise. The vulnerability's ability to escalate privileges within the pipeline context and affect downstream workflows amplifies its impact, making it a critical concern for organizations with complex or multi-stage CI/CD processes.

European organizations should immediately audit their CI/CD pipelines to identify usage of tj-actions/branch-names versions below 9.0.0. The primary mitigation is to upgrade to version 9.0.0 or later, where the vulnerability is fixed. Until upgrades are applied, organizations should implement strict branch and tag naming policies to disallow special characters or patterns that could be exploited for command injection. Additionally, consider isolating GitHub runners with minimal privileges and network segmentation to limit the blast radius of potential exploitation. Employ runtime monitoring and alerting for anomalous command executions within CI/CD environments. Review and restrict permissions of GitHub Actions workflows to the minimum necessary, and audit third-party actions regularly. Finally, incorporate security scanning tools that analyze GitHub Actions workflows for unsafe patterns and enforce secure coding practices in pipeline configurations.