CVE-2021-20285: Upx

Medium severity, CVSS 6.6. EPSS: 0.8% chance of exploitation in the next 30 days.

A flaw was found in upx canPack in p_lx_elf.cpp in UPX 3.96. This flaw allows attackers to cause a denial of service (SEGV or buffer overflow and application crash) or possibly have unspecified other impacts via a crafted ELF. The highest threat from this vulnerability is to system availability.

Affected products

• Upx Upx: version 3.96 only

Published 2021-03-26. Last modified 2026-06-17.