SharpCompress is a fully managed C# library to deal with many compression types and formats. In 0.47.4 and earlier, a path traversal vulnerability in IArchive.WriteToDirectory() allows a malicious archive to create directories outside the intended extraction root. For TAR archives, this can be escalated to arbitrary file writes by chaining with a symlink entry, giving a full write primitive on the target filesystem subject to the permissions of the running process.