CVE-2026-44722 pyzipper: Encryption bypass for small files encrypted with pyzipper
An operator precedence bug in pyzipper caused AES-encrypted files to use a weaker format, exposing CRC32 checksums that allow attackers to brute-force plaintext for small files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44722?
CVE-2026-44722 is a medium-severity vulnerability in danifus pyzipper, published on 17 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
pyzipper is a replacement for Python's zipfile that can read and write AES encrypted zip files. Prior to 0.4.0, a Python operator precedence bug in pyzipper/zipfile_aes.py caused the AE-2 format to never be automatically selected during encryption, causing encrypted entries to be written in AE-1 format and exposing the plaintext CRC32 checksum in the ZIP header and, for unseekable zip archives, in the datadescripter section, allowing an attacker who possesses the archive to brute-force candidate plaintexts for small or low-entropy files by comparing CRC32 values. This issue is fixed in version 0.4.0.
Weakness: CWE-480
Which versions are affected by CVE-2026-44722?
3 open source packages ship an affected version, including pyzipper.
| Package | Affected | Fixed in |
|---|---|---|
pyzipper PyPI | All versions | 0.4.0 |
pyzipper PyPI | All versions | 0.4.0 |
pyzipper PyPI | All versions | 0.4.0 |
How do I fix CVE-2026-44722?
Upgrade pyzipper to 0.4.0 or later.
Is CVE-2026-44722 being exploited?
There is no known exploitation of CVE-2026-44722 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-44722, GHSA-crqm-m339-7m2p, PYSEC-2026-3044, UBUNTU-CVE-2026-44722.