A race condition was addressed with improved locking. This issue is fixed in Security Update 2021-004 Mojave, iOS 14.5 and iPadOS 14.5, watchOS 7.4, Security Update 2021-003 Catalina, tvOS 14.5, macOS Big Sur 11.3. A remote attacker may be able to cause a denial of service.
Published September 8, 2021.