Vulnerability · Published Jul 17, 2026 · Assigned by GitHub_M
CVE-2026-44722pyzipper: Encryption bypass for small files encrypted with pyzipper
Medium 6.2
In plain English
A medium-severity security flaw in pyzipper from danifus. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | python-pyzipper | no fix listed | DEBIAN-CVE-2026-44722 |
| Debian:14 | python-pyzipper | 0.4.0-1 | DEBIAN-CVE-2026-44722 |
| PyPI | pyzipper | 0.4.0 | GHSA-crqm-m339-7m2p |
| PyPI | pyzipper | 0.4.0 | PYSEC-2026-3044 |
| Ubuntu:26.04:LTS | python-pyzipper | no fix listed | UBUNTU-CVE-2026-44722 |
| Ubuntu:26.10 | python-pyzipper | no fix listed | UBUNTU-CVE-2026-44722 |
Affected products (as reported)
Weakness: CWE-480 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
- https://github.com/danifus/pyzipper/security/advisories/GHSA-crqm-m339-7m2p x_refsource_CONFIRM
- https://github.com/danifus/pyzipper/commit/93ce88e7dfd1635443197dab3fb8d477cff579ae x_refsource_MISC
- https://github.com/danifus/pyzipper/releases/tag/v0.4.0 x_refsource_MISC