What’s Vulnerable › Vulnerabilities

CVE-2021-30939

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-08-24 · updated 2026-06-17
• Weakness: CWE-125

Description

An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in macOS Big Sur 11.6.2, tvOS 15.2, macOS Monterey 12.1, Security Update 2021-008 Catalina, iOS 15.2 and iPadOS 15.2, watchOS 8.3. Processing a maliciously crafted image may lead to arbitrary code execution.

Affected products

• Apple iPadOS: before 15.2 — fixed in 15.2
• Apple Iphone Os: before 15.2 — fixed in 15.2
• macOS: from 10.15 before 10.15.7; 10.15.7, 10.15.7-security_update_2020-001, 10.15.7-security_update_2020-005, 10.15.7-security_update_2020-007, 10.15.7-security_update_2021-001, 10.15.7-security_update_2021-002 (+5) — fixed in 10.15.7
• Apple macOS: from 11.0 before 11.6.2; from 12.0 before 12.1 — fixed in 11.6.2, 12.1
• Apple tvOS: before 15.2 — fixed in 15.2
• Apple watchOS: before 8.3 — fixed in 8.3

How to fix

Upgrade to a fixed version: Apple iPadOS 15.2; Apple Iphone Os 15.2; macOS 10.15.7; Apple macOS 11.6.2, 12.1; Apple tvOS 15.2; Apple watchOS 8.3. Check the vendor advisory for mitigations.

References

• https://support.apple.com/en-us/HT212975
• https://support.apple.com/en-us/HT212976
• https://support.apple.com/en-us/HT212978
• https://support.apple.com/en-us/HT212979
• https://support.apple.com/en-us/HT212980
• https://support.apple.com/en-us/HT212981
• https://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1414
• https://www.zerodayinitiative.com/advisories/ZDI-22-359/
• https://support.apple.com/en-us/HT212975
• https://support.apple.com/en-us/HT212976
• https://support.apple.com/en-us/HT212978
• https://support.apple.com/en-us/HT212979

Get alerted when CVE-2021-30939 or the next vulnerability affects your stack