CVE-2026-0123: Google Android Privilege Escalation Flaw

CVE-2026-0123 Overview

CVE-2026-0123 is a high-severity out-of-bounds write vulnerability discovered in Google Android's EfwApTransport::ProcessRxRing function within the efw_ap_transport.cc component. The vulnerability stems from a missing bounds check that could allow a local attacker to achieve privilege escalation without requiring any additional execution privileges or user interaction.

Critical Impact

This vulnerability enables local privilege escalation on affected Android devices. Attackers can exploit this flaw to elevate privileges without user interaction, potentially gaining unauthorized access to sensitive device resources and data.

Affected Products

• Google Android (all versions prior to the March 2026 security patch)

Discovery Timeline

• 2026-03-10 - CVE CVE-2026-0123 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2026-0123

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), a memory corruption flaw that occurs when a program writes data past the boundaries of an allocated buffer. In the context of the EfwApTransport::ProcessRxRing function, the absence of proper bounds validation allows an attacker to write data beyond the intended memory region.

The ProcessRxRing function handles receive ring buffer processing in the Android transport layer. When processing incoming data, the function fails to verify that the data being written fits within the allocated buffer space, creating an exploitable condition for memory corruption.

Root Cause

The root cause of CVE-2026-0123 is a missing bounds check in the EfwApTransport::ProcessRxRing function located in efw_ap_transport.cc. When the function processes data from the receive ring buffer, it does not properly validate the size of incoming data against the allocated buffer boundaries. This allows an attacker to craft malicious input that triggers a write operation beyond the buffer's allocated memory space, corrupting adjacent memory structures.

Attack Vector

The attack vector for this vulnerability is local, requiring the attacker to have some level of access to the target Android device. However, the exploitation does not require any special execution privileges or user interaction, making it particularly dangerous in scenarios where an attacker has gained initial foothold on a device through other means.

An attacker could exploit this vulnerability by:

1. Triggering the vulnerable ProcessRxRing function with specially crafted data
2. Overwriting critical memory structures adjacent to the target buffer
3. Redirecting execution flow to achieve privilege escalation
4. Gaining elevated access to system resources and sensitive data

The vulnerability is particularly concerning as it provides a path to local privilege escalation, which could be chained with other vulnerabilities for complete device compromise.

Detection Methods for CVE-2026-0123

Indicators of Compromise

• Unexpected crashes or instability in Android system services related to transport layer components
• Anomalous memory access patterns in the efw_ap_transport module
• System log entries indicating buffer overflows or memory corruption in transport-related processes
• Unusual privilege escalation events from low-privileged processes

Detection Strategies

• Monitor Android system logs for crashes in transport-related components, particularly those involving EfwApTransport
• Implement runtime memory protection mechanisms that can detect out-of-bounds write attempts
• Deploy endpoint detection solutions capable of identifying privilege escalation attempts on Android devices
• Utilize kernel-level monitoring to detect anomalous memory operations in the affected component

Monitoring Recommendations

• Enable verbose logging for Android system services to capture potential exploitation attempts
• Configure security monitoring solutions to alert on unexpected privilege changes
• Regularly audit device security patch levels to ensure timely remediation
• Monitor for any unusual behavior in applications or processes that interact with the transport layer

How to Mitigate CVE-2026-0123

Immediate Actions Required

• Apply the March 2026 Android security patch immediately on all affected devices
• Review and restrict local access to Android devices in enterprise environments
• Implement mobile device management (MDM) policies to enforce security updates
• Monitor affected devices for signs of exploitation until patches are applied

Patch Information

Google has addressed this vulnerability in the Android Security Bulletin March 2026. Organizations and users should apply the security update as soon as it becomes available for their specific device and carrier combination.

The patch adds proper bounds checking to the EfwApTransport::ProcessRxRing function, ensuring that data writes cannot exceed the allocated buffer boundaries.

Workarounds

• Limit physical access to Android devices to trusted individuals only
• Disable or restrict unnecessary local services that could provide an initial attack vector
• Implement application sandboxing to contain potential privilege escalation attempts
• Consider deploying mobile threat defense solutions that can detect exploitation attempts

# Verify Android security patch level
adb shell getprop ro.build.version.security_patch

# Expected output should be 2026-03-01 or later for patched devices
# If patch level is earlier, prioritize updating the device