What is CVE-2023-22899?

CVE-2023-22899 is a medium-severity vulnerability in Zip4j Project, classified under Origin Validation Error. CVSS score: 5.9/10. Published 2023-01-10.

How severe is CVE-2023-22899?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Vulnerability in Zip4j Project

CVE-2023-22899

Zip4j through 2.11.2, as used in Threema and other products, does not always check the MAC when decrypting a ZIP archive.

Published 2023-01-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.006 (48.0th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000

Affected products

Zip4j Project

Weakness classification (CWE)

CWE-346 — Origin Validation Error

References

breakingthe3ma.app (Third Party Advisory)
breakingthe3ma.app/files/Threema-PST22.pdf (Technical Description, Exploit, Third Party Advisory)
news.ycombinator.com/item (Third Party Advisory)
threema.ch/en/blog/posts/news-alleged-weaknesses-statement (Vendor Advisory)
github.com/srikanth-lingala/zip4j/releases (Third Party Advisory, Release Notes)
github.com/srikanth-lingala/zip4j/issues/485 (Exploit, Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2023-22899?: CVE-2023-22899 is a medium-severity vulnerability in Zip4j Project, classified under Origin Validation Error. CVSS score: 5.9/10. Published 2023-01-10.
How severe is CVE-2023-22899?: Medium severity. CVSS v3 base score is 5.9 out of 10.