CVE-2026-44722
pyzipper: Encryption bypass for small files encrypted with pyzipper
CVSS Score
6.2
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-480 |
| Vendor | danifus |
| Product | pyzipper |
| Published | Jul 17, 2026 |
| Last Updated | Jul 17, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Affected Versions
danifus / pyzipper
< 0.4.0