UPX 4.0.0 Mach-O File p_lx_elf.cpp elf_lookup memory corruption

HistoryDiffrelatejsonxmlCTI

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.4	$0-$5k	0.00

Summaryinfo

A vulnerability was found in UPX 4.0.0 and classified as critical. Affected is the function elf_lookup of the file p_lx_elf.cpp of the component Mach-O File Handler. Executing a manipulation can lead to memory corruption. This vulnerability is handled as CVE-2020-27797. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as critical was found in UPX 4.0.0. This vulnerability affects the function elf_lookup of the file p_lx_elf.cpp of the component Mach-O File Handler. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

An invalid memory address reference was discovered in the elf_lookup function in p_lx_elf.cpp in UPX 4.0.0 via a crafted Mach-O file.

The weakness was released 08/26/2022 as 390. The advisory is shared for download at github.com. This vulnerability was named CVE-2020-27797 since 10/27/2020. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/11/2025).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

Version

4.0.0

License

free

Website

Product: https://github.com/upx/upx/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

10/27/2020 🔍
08/26/2022 +667 days 🔍
08/26/2022 +0 days 🔍
04/11/2025 +959 days 🔍

Sourcesinfo

Product: github.com

Advisory: 390
Status: Confirmed

CVE: CVE-2020-27797 (🔍)
GCVE (CVE): GCVE-0-2020-27797
GCVE (VulDB): GCVE-100-207316

Entryinfo

Created: 08/26/2022 09:04
Updated: 04/11/2025 16:34
Changes: 08/26/2022 09:04 (39), 08/26/2022 09:05 (1), 10/02/2022 07:10 (11), 04/11/2025 16:34 (15)
Complete: 🔍
Cache ID: 216::103