CVE-2026-44722 json
pyzipper: Encryption bypass for small files encrypted with pyzipper
published 5mo ago modified 16d ago also GHSA-crqm-m339-7m2p , PYSEC-2026-3044 , EUVD-2026-45221
- cvss
- 6.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.1%
- EPSS 0.1% chance of exploitation in 30 days, percentile 1%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
Is CVE-2026-44722 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3mo ago
Exploit prediction
0.12% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.2 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| GitHub | 3.1 | 6.2 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| OSV | 3.1 | 6.2 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | pyzipper | <0.4.0 |
0.4.0 |
Affected products
- danifus pyzipper
Classification
- Weakness
-
- CWE-480 Use of Incorrect Operator
References
- github.com /danifus/pyzipper/commit/93ce88e7dfd1635443197dab3fb8d477cff579ae
-
github.com
/danifus/pyzipper/security/advisories/GHSA-crqm-m339-7m2p
web
-
github.com
/danifus/pyzipper/releases/tag/v0.4.0
web
-
github.com
/danifus/pyzipper
package
-
pypi.org
/project/pyzipper
package
-
github.com
/advisories/GHSA-crqm-m339-7m2p
advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-44722
advisory
Sources
- CVE List CVE-2026-44722
- GitHub Advisory GHSA-crqm-m339-7m2p
- NVD CVE-2026-44722
- OSV PYSEC-2026-3044
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.