CVE-2026-49918: Integer Overflow Privilege Escalation

CVE-2026-49918 Overview

CVE-2026-49918 is an out-of-bounds write vulnerability caused by an integer overflow across multiple functions. The flaw enables local privilege escalation on affected systems without requiring user interaction or additional execution privileges. The vulnerability is documented in the Android Security Bulletin September 2026 and is classified under [CWE-787] (Out-of-Bounds Write).

Critical Impact
A local attacker with low privileges can trigger the integer overflow to write outside allocated memory boundaries, achieving elevation of privilege on the host device.

Affected Products

Android platform components referenced in the September 2026 Android Security Bulletin
Devices receiving the 2026-09-01 security patch level
Downstream Android distributions incorporating the vulnerable functions

Discovery Timeline

2026-09-08 - CVE-2026-49918 published to NVD
2026-09-10 - Last updated in NVD database

Technical Details for CVE-2026-49918

Vulnerability Analysis

The vulnerability stems from an integer overflow condition present in multiple functions within the affected code paths. When arithmetic operations on size or index values exceed the maximum representable integer, the resulting wrapped value bypasses bounds checks. Subsequent memory operations use the corrupted size to write past the end of the allocated buffer.

This produces an out-of-bounds write primitive that an attacker can leverage to corrupt adjacent memory structures. Because the flaw resides in privileged code, successful exploitation results in local elevation of privilege. No user interaction is required, and the attacker only needs prior local access with limited privileges.

Root Cause

The root cause is unchecked integer arithmetic used to compute buffer sizes or offsets. When the computed value overflows, validation logic accepts it as legitimate. The overflowed size is then passed to memory write operations, causing writes beyond the intended buffer boundary as classified under [CWE-787].

Attack Vector

Exploitation requires local access to the target device with low-privileged execution rights. An attacker supplies crafted inputs that trigger the arithmetic overflow inside one of the affected functions. The out-of-bounds write then corrupts kernel or privileged process memory, enabling privilege escalation to a higher security context. Refer to the Android Security Bulletin September 2026 for details on the vulnerable components.

Detection Methods for CVE-2026-49918

Indicators of Compromise

Unexpected crashes or kernel oops entries in system logs referencing the affected components
Processes running with elevated privileges that were spawned from low-privileged application contexts
Anomalous memory access violations recorded during runtime instrumentation

Detection Strategies

Monitor Android security patch levels across the device fleet and flag devices below 2026-09-01
Inspect installed applications for local exploit payloads targeting kernel or system-service surfaces
Correlate crash telemetry with privilege changes to identify potential exploitation attempts

Monitoring Recommendations

Enable mobile threat defense telemetry to capture privilege transitions and abnormal syscall patterns
Aggregate device patch-level compliance data into a centralized security data platform for continuous review
Alert on repeated segmentation faults or SELinux denials originating from unprivileged user processes

How to Mitigate CVE-2026-49918

Immediate Actions Required

Apply the September 2026 Android security patch level (2026-09-01) to all managed devices
Enforce mobile device management policies that block enrollment of devices missing the required patch level
Restrict installation of untrusted applications that could deliver a local exploitation payload

Patch Information

The fix is delivered through the Android Security Bulletin September 2026. Device manufacturers and carriers distribute the corresponding over-the-air update. Confirm remediation by verifying the security patch level reports 2026-09-01 or later under device settings.

Workarounds

Limit local access to affected devices by enforcing strong authentication and screen-lock policies
Disable sideloading and restrict application installation to vetted enterprise sources until patching is complete
Segment high-value mobile assets from untrusted networks to reduce the risk of local exploit delivery

bash

# Verify the Android security patch level on a managed device
adb shell getprop ro.build.version.security_patch
# Expected output for remediation: 2026-09-01 or later