What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 6.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-17 · updated 2026-10-24
• Weakness: CWE-480

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 products

• danifus pyzipper: before 0.4.0

References

• https://github.com/danifus/pyzipper/commit/93ce88e7dfd1635443197dab3fb8d477cff579ae
• https://github.com/danifus/pyzipper/releases/tag/v0.4.0
• https://github.com/danifus/pyzipper/security/advisories/GHSA-crqm-m339-7m2p

Get alerted when CVE-2026-44722 or the next vulnerability affects your stack