#VU23826 Out-of-bounds read in UPX - CVE-2019-20021

Vulnerability identifier: #VU23826

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2019-20021

CWE-ID: CWE-125

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
UPX
Universal components / Libraries / Libraries used by multiple products

Vendor: UPX

Description

The vulnerability allows an attacker to gain access to potentially sensitive information.

The vulnerability exists due to a heap-based buffer over-read within the canUnpack() function in p_mach.cpp. An attacker can create a specially crafted Mach-O file, trick the victim into opening it, trigger out-of-bounds read error and read contents of memory on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

UPX: 3.95

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External links
https://github.com/upx/upx/issues/315

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.