Apple iOS, iPadOS, macOS, watchOS Kernel Memory Corruption Vulnerability (CVE-2021-30807) Analysis and Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTApple macOS Big Sur prior to 11.5.1, iOS prior to 14.7.1, iPadOS prior to 14.7.1, and watchOS prior to 7.6.1
A local application can exploit this vulnerability to execute arbitrary code with kernel privileges, leading to complete system compromise. Active exploitation in the wild has been reported
Immediately apply the official software updates provided by Apple to patch the affected systems
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
The primary remediation is to upgrade the operating system to the patched versions released by Apple. For enterprise macOS fleets, administrators can force updates via MDM or execute the following terminal commands.
To check and apply software updates on macOS via terminal:
# List all available software updates
softwareupdate -l
# Download and install all recommended updates and restart automatically
sudo softwareupdate -iaR2. Temporary Workaround & Hardening Configuration
Because this is a kernel-level vulnerability, there are no direct workarounds other than restricting the execution of untrusted applications. Enforce strict Gatekeeper policies on macOS to prevent unauthorized software execution.
# Enable Gatekeeper to restrict execution to App Store and identified developers
sudo spctl --master-enable
# Verify the current Gatekeeper status
spctl --status3. Log Audit & IoC Verification Commands
Use the following script to audit the current operating system version and identify vulnerable endpoints within your environment.
# Query macOS product version and build number
os_version=$(sw_vers -productVersion)
build_version=$(sw_vers -buildVersion)
echo 'Current macOS Version:' $os_version ' (Build:' $build_version ')'
# For iOS/iPadOS devices, query OS versions via MDM inventory to flag versions below 14.7.1.Block Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2021-30807) is a critical memory corruption issue, specifically classified as an Out-of-bounds Write (CWE-787), within the Apple operating system kernel. The root cause lies in inadequate memory handling and boundary validation when processing specific inputs in the kernel space, allowing data to be written outside the allocated buffer limits.
2. Exploitation Mechanics & Attack Scenario
An attacker exploits this vulnerability by executing a specially crafted local application on the target device. This application invokes vulnerable kernel APIs or driver interfaces, passing malicious payloads designed to trigger the boundary validation failure. Upon processing, the kernel overwrites critical memory structures (such as function pointers or object metadata), enabling the attacker to hijack the execution flow and run arbitrary code with Ring 0 (kernel) privileges.
3. Infrastructure & Business Impact
Given that this vulnerability is listed in the CISA KEV catalog, it represents a highly active threat vector that has been exploited in real-world targeted attacks. Successful exploitation bypasses all application sandboxes, allowing attackers to install persistent rootkits, perform keylogging, and exfiltrate sensitive corporate data. Compromised endpoints can serve as initial access points for lateral movement within enterprise networks.
Official Vendor Advisories & References
A memory corruption issue was addressed with improved memory handling. This issue is fixed in macOS Big Sur 11.5.1, iOS 14.7.1 and iPadOS 14.7.1, watchOS 7.6.1. An application may be able to execute arbitrary code with kernel privileges. Apple is aware of a report that this issue may have been actively exploited.
Frequently Asked SecOps Questions (CVE-2021-30807)
FAQQ1. How critical is CVE-2021-30807 and is it actively exploited in the wild?
CVE-2021-30807 is rated CVSS 7.8 (HIGH) with a 30-day EPSS exploitation probability of 28.8%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2021-30807?
Primary impacted vendors include apple across macos, ios, ipados, watchos. Scope summary: Apple macOS Big Sur versions prior to 11.5.1, iOS and iPadOS versions prior to 14.7.1, and watchOS versions prior to 7.6.1
Q3. What temporary mitigations or workarounds exist for CVE-2021-30807 before patching?
[Mitigation] Immediately apply the official software updates provided by Apple to patch the affected systems Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2021-30807
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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