What’s Vulnerable › Vulnerabilities

CVE-2021-1876

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% 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-416

Description

A use after free issue was addressed with improved memory management. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave. Processing maliciously crafted web content may lead to arbitrary code execution.

Affected products

• macOS: from 10.14 through 10.14.5; from 10.15 through 10.15.5; 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)
• 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-2021-1876 or the next vulnerability affects your stack