An anonymous reader writes: Github has announced a security vulnerability and has encourage users to update their Git clients as soon as possible. The blog post reads in part: "A critical Git security vulnerability has been announced today, affecting all versions of the official Git client and all related software that interacts with Git repositories, including GitHub for Windows and GitHub for Mac. Because this is a client-side only vulnerability, github.com and GitHub Enterprise are not directly affected. The vulnerability concerns Git and Git-compatible clients that access Git repositories in a case-insensitive or case-normalizing filesystem. An attacker can craft a malicious Git tree that will cause Git to overwrite its own .git/config file when cloning or checking out a repository, leading to arbitrary command execution in the client machine. Git clients running on OS X (HFS+) or any version of Microsoft Windows (NTFS, FAT) are exploitable through this vulnerability. Linux clients are not affected if they run in a case-sensitive filesystem....Updated versions of GitHub for Windows and GitHub for Mac are available for immediate download, and both contain the security fix on the Desktop application itself and on the bundled version of the Git command-line client."