What’s Vulnerable › Vulnerabilities

CVE-2021-1834

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.0% 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-787

Description

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave. A malicious application may be able to execute arbitrary code with kernel privileges.

Affected products

• macOS: 10.14, 10.14.0, 10.14.1, 10.14.2, 10.14.3, 10.14.4 (+32)
• Apple macOS: from 11.0 before 11.3 — fixed in 11.3

How to fix

Upgrade to a fixed version: Apple macOS 11.3. Check the vendor advisory for mitigations.

References

• https://support.apple.com/en-us/HT212325
• https://support.apple.com/en-us/HT212326
• https://support.apple.com/en-us/HT212327
• https://support.apple.com/en-us/HT212325
• https://support.apple.com/en-us/HT212326
• https://support.apple.com/en-us/HT212327

Get alerted when CVE-2021-1834 or the next vulnerability affects your stack