CVE-2025-54416 is a critical command injection vulnerability identified in the GitHub Actions repository tj-actions/branch-names, specifically affecting versions prior to 9.0.0. This repository provides workflows to retrieve branch or tag names with support for all GitHub event types. The vulnerability stems from improper neutralization of special elements used in command execution (CWE-77), where inconsistent input sanitization and unescaped output allow malicious actors to craft branch or tag names that lead to arbitrary command execution within downstream workflows. Although internal sanitization mechanisms exist, the action's outputs remain vulnerable, exposing any consuming workflows that utilize this action to significant security risks. The vulnerability has a CVSS 3.1 base score of 9.1, indicating a critical severity level. The vector indicates network attack vector (AV:N), low attack complexity (AC:L), requires privileges (PR:L), no user interaction (UI:N), scope changed (S:C), with high confidentiality impact (C:H), low integrity impact (I:L), and low availability impact (A:L). This means an attacker with some level of privileges in the repository can exploit this vulnerability remotely without user interaction, potentially leading to full disclosure of sensitive information, partial integrity loss, and some availability degradation. The vulnerability is fixed in version 9.0.0 of the branch-names action. No known exploits have been reported in the wild yet, but the critical nature and ease of exploitation make it a high-risk issue for organizations using this GitHub Action in their CI/CD pipelines.

For European organizations, this vulnerability poses a significant risk to the integrity and confidentiality of their software development lifecycle. Organizations relying on GitHub Actions for CI/CD automation that incorporate the vulnerable tj-actions/branch-names workflow may inadvertently execute malicious commands embedded in branch or tag names. This can lead to unauthorized code execution, data leakage, or disruption of build and deployment processes. Given the widespread adoption of GitHub and GitHub Actions across European enterprises, especially in technology, finance, and critical infrastructure sectors, exploitation could result in intellectual property theft, compromise of sensitive customer data, or sabotage of production environments. The vulnerability's ability to escalate privileges within workflows means that even users with limited repository permissions could trigger severe consequences. Additionally, the interconnected nature of modern DevOps pipelines means that a single compromised workflow could cascade into broader organizational impact, affecting compliance with GDPR and other data protection regulations.

European organizations should immediately audit their GitHub repositories and workflows 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 patched. Beyond upgrading, organizations should implement strict input validation and sanitization on all user-controlled inputs, including branch and tag names, within their workflows. Employing workflow-level security best practices such as least privilege principles for GitHub tokens, restricting workflow triggers to trusted contributors, and enabling branch protection rules can reduce the attack surface. Additionally, organizations should monitor CI/CD logs for unusual command executions or unexpected workflow behavior. Implementing automated dependency scanning tools that detect vulnerable GitHub Actions can help maintain ongoing security hygiene. Finally, consider isolating critical workflows in separate repositories or environments to limit potential blast radius if exploitation occurs.