What’s Vulnerable › Vulnerabilities

CVE-2021-1776

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-04-02 · 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 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. Processing a maliciously crafted font file may lead to arbitrary code execution.

Affected products

• Apple iPadOS: before 14.4 — fixed in 14.4
• Apple Iphone Os: before 14.4 — fixed in 14.4
• macOS: from 10.14 before 10.14.6; from 10.15 before 10.15.7; 10.14.6, 10.14.6-security_update_2019-004, 10.14.6-security_update_2019-005, 10.14.6-security_update_2019-006, 10.14.6-security_update_2019-007, 10.14.6-security_update_2020-001 (+10) — fixed in 10.14.6, 10.15.7
• Apple macOS: from 11.0 before 11.2 — fixed in 11.2
• Apple tvOS: before 14.4 — fixed in 14.4
• Apple watchOS: before 7.3 — fixed in 7.3

How to fix

Upgrade to a fixed version: Apple iPadOS 14.4; Apple Iphone Os 14.4; macOS 10.14.6, 10.15.7; Apple macOS 11.2; Apple tvOS 14.4; Apple watchOS 7.3. Check the vendor advisory for mitigations.

References

• https://support.apple.com/en-us/HT212146
• https://support.apple.com/en-us/HT212147
• https://support.apple.com/en-us/HT212148
• https://support.apple.com/en-us/HT212149
• https://support.apple.com/en-us/HT212146
• https://support.apple.com/en-us/HT212147
• https://support.apple.com/en-us/HT212148
• https://support.apple.com/en-us/HT212149

Get alerted when CVE-2021-1776 or the next vulnerability affects your stack