Vulnerability Monitor

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CVE-2021-30500

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.8, requiring local system access to exploit with relatively low complexity though user interaction is required and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 3 products from upx, from redhat, from fedoraproject organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2021-05-27T00:15:08.483

Last Modified

2025-04-11T12:27:55.013

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 7.8 (HIGH)

CVSSv2 Vector

AV:N/AC:M/Au:N/C:P/I:P/A:P

Access Vector: NETWORK
Access Complexity: MEDIUM
Authentication: NONE
Confidentiality Impact: PARTIAL
Integrity Impact: PARTIAL
Availability Impact: PARTIAL

Exploitability Score

8.6

Impact Score

6.4

Weaknesses

Type: Secondary
CWE-476

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	upx	upx	4.0.0	Yes
Operating System	redhat	enterprise_linux	7.0	Yes
Operating System	fedoraproject	fedora	33	Yes

References

https://bugzilla.redhat.com/show_bug.cgi?id=1948692 Issue Tracking, Third Party Advisory ([email protected])
https://github.com/upx/upx/commit/90279abdfcd235172eab99651043051188938dcc Patch, Third Party Advisory ([email protected])
https://github.com/upx/upx/issues/485 Exploit, Issue Tracking, Third Party Advisory ([email protected])
https://bugzilla.redhat.com/show_bug.cgi?id=1948692 Issue Tracking, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/upx/upx/commit/90279abdfcd235172eab99651043051188938dcc Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/upx/upx/issues/485 Exploit, Issue Tracking, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For upx's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.