A critical command injection vulnerability, identified as CVE-2025-11148, has been discovered in all versions of the check-branches package. An attacker can exploit this flaw by crafting a malicious git branch name, which, when processed by the tool, allows for the execution of arbitrary commands on the underlying system, potentially leading to a full system compromise.

The check-branches command-line tool is vulnerable to command injection. The tool processes git branch names without proper input sanitization before using them in a shell command. An attacker can create a git branch with a name containing malicious shell metacharacters (e.g., ;, |, &&, $()). When the check-branches tool is executed locally or within an automated CI/CD pipeline, the malicious payload in the branch name is executed with the permissions of the user or service running the tool, leading to arbitrary code execution.

This vulnerability is rated as critical severity with a CVSS score of 9.8. Successful exploitation could lead to a complete compromise of the system running the check-branches tool, which is often a developer workstation or a critical CI/CD build server. The potential consequences include theft of source code, proprietary data, and sensitive credentials (API keys, passwords, SSH keys); injection of malicious code into the software supply chain; and using the compromised system as a pivot point to attack other internal network resources. This poses a severe risk of data breach, intellectual property loss, and significant operational disruption.

Immediate Action: Immediately apply the security update provided by the vendor. All systems using the check-branches package should be patched to the latest version to mitigate this vulnerability. After patching, it is crucial to monitor systems for any signs of exploitation and thoroughly review access logs and command history on potentially affected systems (e.g., CI/CD servers, developer machines).

Proactive Monitoring: Implement enhanced monitoring on systems where the check-branches tool is used. Security teams should look for suspicious process execution originating from the CI/CD pipeline or developer tools. Monitor shell logs (e.g., bash_history, auditd, Sysmon) for unusual commands or patterns. Pay close attention to git branch names that contain shell metacharacters or command-like syntax within your version control system and CI/CD job logs.

Compensating Controls: If immediate patching is not feasible, implement the following compensating controls:

• Run the check-branches tool in a sandboxed, isolated environment (e.g., a minimal container with restricted permissions and no network access).
• Implement strict access control policies on the version control system to limit who can create or rename branches.
• If possible, implement a pre-processing script that sanitizes or validates branch names for malicious characters before they are passed to the check-branches tool.

Public Exploit Available: false

Given the critical severity (CVSS 9.8) of this vulnerability and its potential for complete system compromise, immediate remediation is strongly recommended. Organizations must prioritize patching all systems utilizing the check-branches package, with special attention given to CI/CD environments which are high-value targets for supply chain attacks. Although not currently listed in the CISA KEV catalog, the high impact and ease of exploitation make CVE-2025-11148 a top-priority vulnerability that should be addressed without delay to prevent potential compromise.