CVE-2021-20285

Name: CVE-2021-20285
Creator: NVD / NIST
Published: 2021-03-26T17:15:13.14+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.6/10EPSS 0.75%

Last modified Jun 17, 2026

CVE-2021-20285 is a medium-severity vulnerability rated 6.6/10 on the CVSS scale. 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. EPSS estimates a 0.75% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

6.6/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

EPSS Probability

0.75%

50.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Upx	Upx	3.96

References

https://bugzilla.redhat.com/show_bug.cgi?id=1937787Issue Tracking, Third Party Advisory
https://github.com/upx/upx/issues/421Exploit, Issue Tracking, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1937787Issue Tracking, Third Party Advisory
https://github.com/upx/upx/issues/421Exploit, Issue Tracking, Third Party Advisory

Timeline

Published: Mar 26, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20285?

How severe is CVE-2021-20285?

CVE-2021-20285 has a CVSS score of 6.6/10 (MEDIUM severity). The EPSS model estimates a 0.75% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20285?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20285?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST