CVE-2021-30501

Name: CVE-2021-30501
Creator: NVD / NIST
Published: 2021-05-27T00:15:08.527+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 1.04%

Last modified Jun 17, 2026

CVE-2021-30501 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. An assertion abort was found in upx MemBuffer::alloc() in mem.cpp, in version UPX 4.0.0. The flow allows attackers to cause a denial of service (abort) via a crafted file.. EPSS estimates a 1.04% chance of exploitation in the next 30 days.

Description

An assertion abort was found in upx MemBuffer::alloc() in mem.cpp, in version UPX 4.0.0. The flow allows attackers to cause a denial of service (abort) via a crafted file.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

1.04%

59.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Upx	Upx	4.0.0
Redhat	Enterprise Linux	7.0
Fedoraproject	Fedora	33

References

https://bugzilla.redhat.com/show_bug.cgi?id=1948696Issue Tracking, Patch, Third Party Advisory
https://github.com/upx/upx/commit/28e761cd42211dfe0124b7a29b2f74730f453e46Patch, Third Party Advisory
https://github.com/upx/upx/issues/486Exploit, Issue Tracking, Third Party Advisory
https://github.com/upx/upx/pull/487Exploit, Patch, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1948696Issue Tracking, Patch, Third Party Advisory
https://github.com/upx/upx/commit/28e761cd42211dfe0124b7a29b2f74730f453e46Patch, Third Party Advisory
https://github.com/upx/upx/issues/486Exploit, Issue Tracking, Third Party Advisory
https://github.com/upx/upx/pull/487Exploit, Patch, Third Party Advisory

Timeline

Published: May 27, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-30501?

An assertion abort was found in upx MemBuffer::alloc() in mem.cpp, in version UPX 4.0.0. The flow allows attackers to cause a denial of service (abort) via a crafted file.

How severe is CVE-2021-30501?

CVE-2021-30501 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 1.04% probability of exploitation in the next 30 days.

How do I fix CVE-2021-30501?

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-2021-30501?

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

Scan your code now

Source: NVD / NIST