Overview
A high-severity vulnerability, identified as CVE-2025-66476, affects Vim, a popular open-source command-line text editor, on Windows platforms. This uncontrolled search path vulnerability allows an attacker to execute arbitrary code by placing a malicious executable in the same directory as the file being edited. It’s crucial to update Vim to version 9.1.1947 or later to mitigate this risk.
Technical Details
Vim versions prior to 9.1.1947 on Windows, when using cmd.exe, resolve external commands by searching the current working directory before system paths. This means that when Vim invokes external tools such as findstr (used for :grep), executes external commands or filters via :!, or utilizes compiler/:make commands, it could inadvertently execute a malicious executable if one is present in the same directory as the file being edited.
The vulnerability stems from the way Vim handles the search path for external commands on Windows, prioritizing the current working directory. An attacker can exploit this by crafting a malicious executable (e.g., a fake findstr.exe) and placing it in a directory where a Vim user is likely to open and edit files.
CVSS Analysis
- CVE ID: CVE-2025-66476
- Severity: HIGH
- CVSS Score: 7.8
- The CVSS score reflects the high impact of this vulnerability, as it allows for arbitrary code execution. The attack complexity is relatively low, as it only requires placing a malicious file in a directory the user is likely to access.
Possible Impact
Successful exploitation of CVE-2025-66476 can lead to:
- Arbitrary Code Execution: An attacker can execute arbitrary code with the privileges of the user running Vim.
- Data Theft: Malicious code can be used to steal sensitive data from the affected system.
- System Compromise: The attacker can potentially gain complete control over the affected Windows system.
- Malware Installation: The attacker can install malware, such as ransomware or keyloggers.
Mitigation or Patch Steps
The primary mitigation is to update Vim to version 9.1.1947 or later. You can download the latest version from the official Vim website or use your package manager if available.
- Upgrade Vim: Download and install the latest version of Vim from the official source.
- Verify the Update: After updating, verify the Vim version to ensure that you are running version 9.1.1947 or later.
- Be Cautious: Exercise caution when opening files from untrusted sources, especially in directories that you have not created yourself.
