What’s Vulnerable › Vulnerabilities

CVE-2021-1884

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-09-08 · updated 2026-06-17
• Weakness: CWE-362

Description

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.

Affected products

• Apple iPadOS: before 14.5 — fixed in 14.5
• Apple Iphone Os: before 14.5 — fixed in 14.5
• macOS: from 10.14.0 before 10.14.6; from 10.15 before 10.15.7; 10.14.6, 10.14.6-security_update_2019-001, 10.14.6-security_update_2019-002, 10.14.6-security_update_2019-004, 10.14.6-security_update_2019-005, 10.14.6-security_update_2019-006 (+21) — fixed in 10.14.6, 10.15.7
• Apple macOS: from 11.0 before 11.3 — fixed in 11.3
• Apple tvOS: before 14.5 — fixed in 14.5
• Apple watchOS: before 7.4 — fixed in 7.4

How to fix

Upgrade to a fixed version: Apple iPadOS 14.5; Apple Iphone Os 14.5; macOS 10.14.6, 10.15.7; Apple macOS 11.3; Apple tvOS 14.5; Apple watchOS 7.4. Check the vendor advisory for mitigations.

References

• https://support.apple.com/en-us/HT212317
• https://support.apple.com/en-us/HT212323
• https://support.apple.com/en-us/HT212324
• https://support.apple.com/en-us/HT212325
• https://support.apple.com/en-us/HT212530
• https://support.apple.com/en-us/HT212531
• https://support.apple.com/en-us/HT212317
• https://support.apple.com/en-us/HT212323
• https://support.apple.com/en-us/HT212324
• https://support.apple.com/en-us/HT212325
• https://support.apple.com/en-us/HT212530
• https://support.apple.com/en-us/HT212531

Get alerted when CVE-2021-1884 or the next vulnerability affects your stack