CVE-2021-1775

Apple macOS libFontParser TTF Parsing Integer Underflow Information Disclosure Vulnerability

Severity Score

7.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

This issue was addressed by removing the vulnerable code. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave. Processing a maliciously crafted font may lead to arbitrary code execution.

Este problema es abordado al eliminar el código vulnerable. Este problema es corregido en macOS Big Sur versión 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave. El procesamiento de una fuente diseñada maliciosamente puede conllevar a una ejecución de código arbitraria.

This vulnerability allows remote attackers to disclose sensitive information on affected installations of Apple macOS. Interaction with the libFontParser library is required to exploit this vulnerability but attack vectors may vary depending on the implementation.
The specific flaw exists within the parsing of TTF fonts. The issue results from the lack of proper validation of user-supplied data, which can result in an integer underflow before reading from memory. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the current process.

*Credits: Mickey Jin & Qi Sun of Trend Micro Mobile Security Research Team

CVSS Scores

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-12-08 CVE Reserved
2021-02-04 CVE Published
2024-08-03 CVE Updated
2024-09-05 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (1)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://support.apple.com/en-us/HT212147	2021-04-09

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				>= 10.14 < 10.14.6 Search vendor "Apple" for product "Mac Os X" and version " >= 10.14 < 10.14.6"		-		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				>= 10.15 < 10.15.7 Search vendor "Apple" for product "Mac Os X" and version " >= 10.15 < 10.15.7"		-		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		-		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2019-004		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2019-005		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2019-006		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2019-007		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2020-001		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2020-002		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2020-003		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2020-004		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2020-005		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2020-006		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		security_update_2020-007		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		supplemental_update		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.14.6 Search vendor "Apple" for product "Mac Os X" and version "10.14.6"		supplemental_update_2		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		-		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		supplemental_update		Affected
Apple Search vendor "Apple"		Macos Search vendor "Apple" for product "Macos"				>= 11.0 < 11.2 Search vendor "Apple" for product "Macos" and version " >= 11.0 < 11.2"		-		Affected