pyzipper: Encryption bypass for small files encrypted with pyzipper

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-44722
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-17 17:17:15 UTC
Updated2026-07-17 18:45:20 UTC
Descriptionpyzipper 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.

Risk And Classification

Primary CVSS: v3.1 6.2 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS: 0.000850000 probability, percentile 0.004110000 (date 2026-07-20)

Problem Types: CWE-480 | CWE-480 CWE-480: Use of Incorrect Operator

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.2MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
3.1CNADECLARED6.2MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Danifus Pyzipper affected < 0.4.0 Not specified

References

ReferenceSourceLinkTags
github.com/danifus/pyzipper/releases/tag/v0.4.0 [email protected] github.com
github.com/danifus/pyzipper/security/advisories/GHSA-crqm-m339-7m2p [email protected] github.com
github.com/danifus/pyzipper/commit/93ce88e7dfd1635443197dab3fb8d477cff579ae [email protected] github.com
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