CVE-2026-55318: Use-After-Free Race Condition Vulnerability

CVE-2026-55318 Overview

CVE-2026-55318 is a use-after-free vulnerability caused by a race condition affecting multiple locations within the Android platform. The flaw was disclosed in the Android Security Bulletin September 2026. Concurrent execution paths access freed memory, producing an exploitable memory corruption condition. Successful exploitation can lead to remote code execution without requiring additional execution privileges. User interaction is not required, which broadens the exploitable attack surface. The weakness is classified under [CWE-362] (Concurrent Execution using Shared Resource with Improper Synchronization).

Critical Impact
Attackers can achieve remote code execution on affected Android devices with no user interaction, using a race condition that dereferences freed memory.

Affected Products

Android platform components referenced in the Pixel Security Bulletin (September 2026)
Devices receiving the 2026-09-01 or later Android security patch level
Refer to the vendor advisory for the authoritative list of impacted builds

Discovery Timeline

2026-09-15 - CVE-2026-55318 published to the National Vulnerability Database (NVD)
2026-09-16 - Last updated in the NVD database

Technical Details for CVE-2026-55318

Vulnerability Analysis

The vulnerability is a use-after-free triggered by a race condition present in multiple locations within the affected Android code paths. Two or more threads operate on a shared object without adequate synchronization. One execution path frees the underlying allocation while another retains a stale pointer to the same memory. The stale pointer is later dereferenced, allowing an attacker who controls the reclaimed allocation to influence program state. Because the flaw affects the network attack surface and requires no user interaction, exploitation can be driven remotely once the attacker holds low-level privileges on the device. The result is arbitrary code execution in the context of the vulnerable component.

Root Cause

The root cause is improper synchronization of concurrent access to shared memory resources [CWE-362]. The affected code paths free an object on one thread while another thread continues to hold and use a reference to the same object. The absence of atomic reference tracking or locking around the free operation permits the two operations to interleave. When the allocator returns the freed region to a controlled allocation, the reused reference operates on attacker-influenced data.

Attack Vector

An attacker triggers the race by issuing concurrent operations that force the vulnerable component to free and reuse the same object window. Consistent scheduling pressure and repeated attempts increase the probability of hitting the narrow race window. Once the use-after-free is triggered, the attacker shapes heap layout to place controlled data in the freed slot. Dereferencing the stale pointer then transfers control flow into attacker-controlled memory. The Android Security Bulletin does not publish exploitation code, and no public proof of concept was identified at the time of writing.

Detection Methods for CVE-2026-55318

Indicators of Compromise

Unexpected crashes or tombstone entries in logcat referencing SIGSEGV or SIGABRT in the affected components
Repeated abnormal termination of a system service followed by unexplained process spawns
Kernel or userspace crash reports referencing freed heap addresses under concurrent workloads

Detection Strategies

Monitor Android device logs for repeated crash signatures in components touched by the September 2026 bulletin
Correlate application or service crashes with subsequent privilege changes or new process creation on the endpoint
Track devices reporting security patch levels earlier than 2026-09-01 and flag them as out of compliance

Monitoring Recommendations

Ingest mobile device telemetry into a centralized analytics platform to baseline normal crash rates per component
Alert on anomalous spikes in native crashes originating from the same process across a device fleet
Track patch-level compliance continuously and prioritize devices exposed to untrusted networks

How to Mitigate CVE-2026-55318

Immediate Actions Required

Apply the September 2026 Android security patch (security patch level 2026-09-01 or later) as soon as the OEM makes it available
Inventory managed Android devices and identify those below the required patch level using mobile device management (MDM) reporting
Restrict installation of untrusted applications while patches are being rolled out across the fleet

Patch Information

Google addressed CVE-2026-55318 in the Android Security Bulletin September 2026. Devices with a security patch level of 2026-09-01 or later contain the fix. Pixel and OEM devices should apply the vendor-supplied over-the-air (OTA) update that references this bulletin. Verify remediation by checking the reported security patch level under device settings.

Workarounds

No vendor-published workaround exists; the security patch is the authoritative remediation
Reduce exposure by keeping devices off untrusted networks until the patch is applied
Enforce MDM policies that restrict sideloading and limit background execution of untrusted code

bash

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