UPX 3.95 Mach-O File p_mach.cpp canUnpack out-of-bounds write

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.
5.4	$0-$5k	0.00

Summaryinfo

A vulnerability identified as critical has been detected in UPX 3.95. This affects the function canUnpack of the file p_mach.cpp of the component Mach-O File Handler. This manipulation causes out-of-bounds write. This vulnerability appears as CVE-2019-20021. The attack requires local access. There is no available exploit.

Detailsinfo

A vulnerability has been found in UPX 3.95 and classified as critical. Affected by this vulnerability is the function canUnpack of the file p_mach.cpp of the component Mach-O File Handler. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A heap-based buffer over-read was discovered in canUnpack in p_mach.cpp in UPX 3.95 via a crafted Mach-O file.

The weakness was presented 12/27/2019. This vulnerability is known as CVE-2019-20021 since 12/27/2019. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

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

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

Version

3.95

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: 5.4
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.3
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / 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

12/27/2019 🔍
12/27/2019 +0 days 🔍
12/27/2019 +0 days 🔍
04/11/2025 +1932 days 🔍

Sourcesinfo

Product: github.com

Advisory: 315
Status: Not defined

CVE: CVE-2019-20021 (🔍)
GCVE (CVE): GCVE-0-2019-20021
GCVE (VulDB): GCVE-100-147793

Entryinfo

Created: 12/27/2019 09:04
Updated: 04/11/2025 15:35
Changes: 12/27/2019 09:04 (36), 12/27/2019 09:09 (17), 03/17/2024 14:04 (4), 03/17/2024 14:10 (1), 04/11/2025 15:35 (15)
Complete: 🔍
Cache ID: 216::103