I wrote a small, zero-dependency wrapper for secure ZIP extraction.
https://github.com/barseghyanartur/safezip
What My Project Does
safezip is a zero-dependency wrapper around Python's zipfile module that makes secure ZIP extraction the default. It protects against:
ZipSlip protection: Blocks relative paths, absolute paths, Windows UNC paths, Unicode lookalike attacks, and null bytes in filenames.
ZIP bomb prevention: Enforces per-member and cumulative decompression ratio limits at stream time — not based on untrusted header values.
ZIP64 consistency checks: Crafted archives with inconsistent ZIP64 extra fields are rejected before decompression begins.
Symlink policy — configurable: REJECT (default), IGNORE, or RESOLVE_INTERNAL.
Atomic writes: Extracts to a temp file first and only moves it to the destination if all checks pass. If something fails, you don't end up with half-extracted junk on your disk.
Environment variable overrides: All numeric limits can be set via SAFEZIP_* environment variables for containerised deployments.
It's meant to be an almost drop-in replacement. You can just do:
from safezip import safe_extract
safe_extract("path/to/file.zip", "/var/files/extracted/")
If you need more control, there’s a SafeZipFile context manager that lets you tweak limits or monitor security events.
from safezip import SafeZipFile
with SafeZipFile("path/to/file.zip") as zf:
print(zf.namelist())
zf.extractall("/var/files/extracted/")
Target Audience
If you're handling user uploads or processing ZIP files from untrusted sources, this might save you some headache. It's production-oriented but currently in beta, so feedback and edge cases are very welcome.
Comparison
The standard library's zipfile module historically wasn't safe to use on untrusted files. Even the official docs warn against extractall() because of ZipSlip risks, and it doesn't do much to stop ZIP bombs from eating up your disk or memory. Python 3.12 did address some of this — extractall() now strips path components that would escape the target directory — but it still leaves meaningful gaps: no ZIP bomb protection, no stream-time size enforcement, no symlink policy, no ZIP64 consistency checks, and no atomic writes. safezip fills all of those. I got tired of writing the same boilerplate every time, so I packaged it up.
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Documentation: https://safezip.readthedocs.io/en/latest/
