CVE-2021-1884

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

1.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-09-08 15:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:32 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.6% in the next 30 days (EPSS).
• Severity: 5.9 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-09-08 15:15 UTC

Last modified

2026-06-17 03:32 UTC

Exploit probability

1.6% · EPSS, next 30 days

Weakness

CWE-362 · Race condition

Record status

Modified

Affected

• Apple Ipados < 14.5
• Apple Iphone Os < 14.5
• Apple Mac Os X < 10.14.6
• Apple Mac Os X < 10.15.7
• Apple Mac Os X 10.14.6
• Apple Mac Os X 10.15.7
• Apple macOS < 11.3
• Apple Tvos < 14.5

Attack profile CVSS 3.1 · 5.9

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

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