Vulnerabilities affecting this package (0)
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This package is not known to be affected by vulnerabilities.
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Vulnerabilities fixed by this package (1)
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VCID-qj1y-b8m1-hyfm
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tar-rs `unpack_in` can chmod arbitrary directories by following symlinks
## Summary
When unpacking a tar archive, the `tar` crate's `unpack_dir` function uses `fs::metadata()` to check whether a path that already exists is a directory. Because `fs::metadata()` follows symbolic links, a crafted tarball containing a symlink entry followed by a directory entry with the same name causes the crate to treat the symlink target as a valid existing directory — and subsequently apply `chmod` to it. This allows an attacker to modify the permissions of arbitrary directories outside the extraction root.
## Reproducer
A malicious tarball contains two entries: (1) a symlink `foo` pointing to an arbitrary external directory, and (2) a directory entry `foo/.` (or just `foo`). When unpacked, `create_dir("foo")` fails with `EEXIST` because the symlink is already on disk. The `fs::metadata()` check then follows the symlink, sees a directory at the target, and allows processing to continue. The directory entry's mode bits are then applied via `chmod`, which also follows the symlink — modifying the permissions of the external target directory.
## Fix
The fix is very simple, we now use `fs::symlink_metadata()` in `unpack_dir`, so symlinks are detected and rejected rather than followed.
## Credit
This issue was reported by @xokdvium - thank you!
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CVE-2026-33056
GHSA-j4xf-2g29-59ph
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