CVE-2026-44722pyzipper: Encryption bypass for small files encrypted with pyzipper
- 6.2MediumCVSS base score
- 0.12%Exploitation in 30 daysEPSS · top 98% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By GitHub_M
- 2 months later
· 2 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium6.2 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| NVDNVD · Deferred | 3.1 | Medium6.2 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.12% · top 98% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.2.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIpyzipperGHSA-crqm-m339-7m2p (opens in a new tab)
References
References3
- https://github.com/danifus/pyzipper/security/advisories/GHSA-crqm-m339-7m2p (opens in a new tab)x_refsource_CONFIRM
- https://github.com/danifus/pyzipper/commit/93ce88e7dfd1635443197dab3fb8d477cff579ae (opens in a new tab)x_refsource_MISC
- https://github.com/danifus/pyzipper/releases/tag/v0.4.0 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-45221 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-crqm-m339-7m2p (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-44722)Record last updated .