CVE-2023-45853: Smihica Pyminizip

Critical severity, CVSS 9.8. EPSS: 3.2% chance of exploitation in the next 30 days.

MiniZip in zlib through 1.3 has an integer overflow and resultant heap-based buffer overflow in zipOpenNewFileInZip4_64 via a long filename, comment, or extra field. NOTE: MiniZip is not a supported part of the zlib product. NOTE: pyminizip through 0.2.6 is also vulnerable because it bundles an affected zlib version, and exposes the applicable MiniZip code through its compress API.

Affected products

• Smihica Pyminizip: up to and including 0.2.6
• Zlib Zlib: before 1.3.1 (fixed in 1.3.1)

Published 2023-10-14. Last modified 2026-07-14.