What’s Vulnerable › Vulnerabilities

CVE-2021-1878

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.8% 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-190

Description

An integer overflow was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave. An attacker in a privileged network position may be able to leak sensitive user information.

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 (+20)
• 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

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