An integer overflow was addressed with improved input validation. This issue is fixed in Security Update 2021-005 Catalina, iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6, watchOS 7.6.2. Processing a maliciously crafted PDF may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.
https://support.apple.com/en-us/HT212806
https://support.apple.com/en-us/HT212807
https://support.apple.com/en-us/HT212804
https://support.apple.com/en-us/HT212805
http://seclists.org/fulldisclosure/2021/Sep/26
http://seclists.org/fulldisclosure/2021/Sep/25
http://seclists.org/fulldisclosure/2021/Sep/28
http://seclists.org/fulldisclosure/2021/Sep/27
http://seclists.org/fulldisclosure/2021/Sep/39
http://seclists.org/fulldisclosure/2021/Sep/38
http://seclists.org/fulldisclosure/2021/Sep/40
https://support.apple.com/kb/HT212824
http://seclists.org/fulldisclosure/2021/Sep/50
Source: MITRE
Published: 2021-08-24
Updated: 2022-09-30
Type: CWE-190
Base Score: 6.8
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 7.8
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 1.8
Severity: HIGH