CVE-2026-20620: macOS Buffer Overflow Vulnerability

CVE-2026-20620 Overview

CVE-2026-20620 is an out-of-bounds read vulnerability affecting multiple versions of Apple macOS. The vulnerability stems from insufficient input validation, which can allow an attacker to cause unexpected system termination or read sensitive kernel memory. This type of memory corruption issue represents a significant security concern as it may lead to information disclosure from protected kernel address space.

Critical Impact

Attackers may exploit this vulnerability to crash affected systems or extract sensitive information from kernel memory, potentially exposing cryptographic keys, credentials, or other privileged data.

Affected Products

• macOS Sequoia versions prior to 15.7.4
• macOS Tahoe versions prior to 26.3
• macOS Sonoma versions prior to 14.8.4

Discovery Timeline

• 2026-02-11 - CVE-2026-20620 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2026-20620

Vulnerability Analysis

This out-of-bounds read vulnerability occurs when the macOS kernel processes certain input without proper bounds checking. When exploited, an attacker can trigger memory reads beyond the intended buffer boundaries. The consequences include two potential attack outcomes: denial of service through unexpected system termination, and information disclosure through reading kernel memory contents.

Out-of-bounds read vulnerabilities in kernel space are particularly dangerous because they can expose memory that contains sensitive system data, kernel pointers, or security-critical information that could be leveraged for further attacks such as privilege escalation or bypassing security mechanisms like KASLR (Kernel Address Space Layout Randomization).

Root Cause

The root cause of this vulnerability is improper input validation within the macOS kernel. When processing specific input data, the kernel fails to adequately verify that memory access operations stay within the bounds of allocated buffers. This allows read operations to access memory locations outside the intended data structure, leading to potential information leakage or system instability.

Attack Vector

The specific attack vector for CVE-2026-20620 has not been publicly detailed by Apple. However, out-of-bounds read vulnerabilities in macOS kernels typically require either local access or the ability to deliver malicious input to a vulnerable kernel component. The attacker would need to craft specific input that triggers the vulnerable code path and causes the kernel to read memory beyond its intended boundaries.

Exploitation could result in:

• Disclosure of sensitive kernel memory contents
• System crashes causing denial of service
• Potential foundation for more sophisticated attacks when combined with other vulnerabilities

Detection Methods for CVE-2026-20620

Indicators of Compromise

• Unexpected kernel panics or system crashes without clear cause
• Unusual system behavior indicating memory corruption
• Evidence of repeated crash attempts suggesting exploitation activity
• Anomalous kernel log entries related to memory access violations

Detection Strategies

• Monitor system logs for kernel panic events and memory-related errors
• Deploy endpoint detection and response (EDR) solutions capable of detecting memory corruption exploitation attempts
• Implement SentinelOne's behavioral AI to identify anomalous kernel-level activity
• Review system crash reports for patterns indicative of exploitation attempts

Monitoring Recommendations

• Enable verbose kernel logging to capture memory-related events
• Configure SentinelOne agents to monitor for kernel exploitation indicators
• Establish baseline system behavior to identify anomalies that may indicate attack attempts
• Monitor for unusual application crashes that could indicate reconnaissance or exploitation

How to Mitigate CVE-2026-20620

Immediate Actions Required

• Update macOS Sequoia to version 15.7.4 or later
• Update macOS Tahoe to version 26.3 or later
• Update macOS Sonoma to version 14.8.4 or later
• Review Apple security advisories for additional guidance and context

Patch Information

Apple has addressed this vulnerability through improved input validation in the affected macOS versions. Security patches are available through the standard macOS Software Update mechanism. Organizations should prioritize applying these updates to all affected systems.

For detailed patch information, refer to the following Apple Security Advisories:

• Apple Security Advisory #126348
• Apple Security Advisory #126349
• Apple Security Advisory #126350

Workarounds

• Limit local access to affected systems to trusted users only
• Implement network segmentation to reduce exposure of vulnerable systems
• Deploy endpoint protection solutions like SentinelOne to detect exploitation attempts
• Monitor systems closely for signs of compromise until patches can be applied

# Check current macOS version
sw_vers -productVersion

# Trigger software update check
softwareupdate --list

# Install all available security updates
softwareupdate --install --all