Git is a revision control system. Prior to versions 2.45.1, 2.44.1, 2.43.4, 2.42.2, 2.41.1, 2.40.2, and 2.39.4, repositories with submodules can be crafted in a way that exploits a bug in Git whereby it can be fooled into writing files not into the submodule's worktree but into a .git/ directory. This allows writing a hook that will be executed while the clone operation is still running, giving the user no opportunity to inspect the code that is being executed. The problem has been patched in versions 2.45.1, 2.44.1, 2.43.4, 2.42.2, 2.41.1, 2.40.2, and 2.39.4. If symbolic link support is disabled in Git (e.g. via git config --global core.symlinks false), the described attack won't work. As always, it is best to avoid cloning repositories from untrusted sources.
Git is a source code management tool. When cloning from a server (or fetching, or pushing), informational or error messages are transported from the remote Git process to the client via the so-called "sideband channel". These messages will be prefixed with "remote:" and printed directly to the standard error output. Typically, this standard error output is connected to a terminal that understands ANSI escape sequences, which Git did not protect against. Most modern terminals support control sequences that can be used by a malicious actor to hide and misrepresent information, or to mislead the user into executing untrusted scripts. As requested on the git-security mailing list, the patches are under discussion on the public mailing list. Users are advised to update as soon as possible. Users unable to upgrade should avoid recursive clones unless they are from trusted sources.
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals. Git defines a line-based protocol that is used to exchange information between Git and Git credential helpers. Some ecosystems (most notably, .NET and node.js) interpret single Carriage Return characters as newlines, which renders the protections against CVE-2020-5260 incomplete for credential helpers that treat Carriage Returns in this way. This issue has been addressed in commit b01b9b8 which is included in release versions v2.48.1, v2.47.1, v2.46.3, v2.45.3, v2.44.3, v2.43.6, v2.42.4, v2.41.3, and v2.40.4. Users are advised to upgrade. Users unable to upgrade should avoid cloning from untrusted URLs, especially recursive clones.
Git does not sanitize URLs when asking for credentials interactively