All versions of sevenz-rust fail to validate file paths when extracting in decompress impl (the underlying function used in the exposed decompress api functions).

This oversight allows a maliciously crafted archive to extract outside the extraction directory, from both relative paths such as ../../../... or absolute paths like C:... or /etc/..., which could lead to file disclosure or remote command execution in combination with other flaws or social engineering.

The following line numbers will be referencing the latest version v0.6.1. The specific point of failure is at de funcs.rs::101 inside decompress impl.

seven.for each entries(|entry, reader| {
  let dest path = dest.join(entry.name());
  extract fn(entry, reader, &dest path)
})?;

When the function iterates through each entry, it blindly joins the entry name with the output directory before passing the path into extract fn, default entry extract fn unless specified otherwise by user. This allows for relative path traversal from simple path concatenation and absolute path traversal due to std::path::join's edge case where if the "[passed] path is absolute, it replaces the current path."

default entry extract fn also fails to validate if the entry it is given has a safe extraction path before it writes to disk at de funcs.rs::135.

The project has been abandoned and the repository has been deleted, so no upstream fix is expected. Users should migrate away from the library in favor of a modern up-to-date 7z library such as sevenz-rust2.