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CVE-2026-44722

CVE-2026-44722 · pyzipper: Encryption bypass for small files encrypted with pyzipper

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 6.2 · Medium · EPSS 0.1% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • pyzipper

    Versions
    • < 0.4.0: Affected

    No fix published

  • python-pyzipper Debian:13

    Versions
    • 0.3.6-5
    • 0.4.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-pyzipper Debian:14

    Versions
    • 0.3.6-5
    Affected ranges
    • ECOSYSTEM: < 0.4.0-1

    Update to 0.4.0-1

  • pyzipper PyPI

    Versions
    • 0.1.0
    • 0.2.0
    • 0.3.0
    • 0.3.1
    • 0.3.2
    • 0.3.3
    • 0.3.4
    • 0.3.5
    • 0.3.6
    Affected ranges
    • ECOSYSTEM: < 0.4.0

    Update to 0.4.0

  • python-pyzipper Ubuntu:26.10

    Versions
    • 0.3.6-5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-pyzipper Ubuntu:26.04:LTS

    Versions
    • 0.3.6-5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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