CVE-2025-48539 Overview
CVE-2025-48539 is a use-after-free vulnerability in the SendPacketToPeer function of acl_arbiter.cc within the Android Bluetooth module. The flaw enables an out-of-bounds read that can lead to remote code execution over an adjacent network. Exploitation requires no user interaction and no additional execution privileges, making it viable for proximity-based attacks against Android 15 and Android 16 devices. Google addressed the issue in the September 2025 Android Security Bulletin.
Critical Impact
An attacker within Bluetooth range can trigger memory corruption in the Android Bluetooth stack and achieve remote code execution without user interaction.
Affected Products
- Google Android 15.0
- Google Android 16.0
- Android Bluetooth module (packages/modules/Bluetooth)
Discovery Timeline
- 2025-09-04 - CVE-2025-48539 published to the National Vulnerability Database
- 2025-09-01 - Fix included in the Android Security Bulletin September 2025
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-48539
Vulnerability Analysis
The vulnerability resides in the SendPacketToPeer function inside acl_arbiter.cc, part of the Android Bluetooth Access Control List (ACL) arbitration logic. The code accesses a memory region after it has been freed, resulting in an out-of-bounds read against reclaimed heap memory. Attackers can leverage this dangling reference to leak sensitive data or manipulate control flow when the freed allocation is reused by attacker-controlled content.
The issue is categorized as CWE-416: Use After Free. Because the flaw is reachable from the Bluetooth attack surface, exploitation does not require any authentication step from the victim or interaction from the device user.
Root Cause
The root cause is improper lifetime management of a Bluetooth ACL data structure referenced by SendPacketToPeer. When a peer connection state changes, the associated buffer is deallocated while another code path still holds a pointer to it. Subsequent packet transmission logic dereferences that stale pointer, reading beyond the bounds of the newly reallocated memory.
Attack Vector
An attacker within Bluetooth range of a vulnerable device can send crafted ACL packets that trigger the race between connection teardown and packet transmission. Because the attack vector is Adjacent Network, physical proximity or a Bluetooth-capable relay is required rather than remote internet access. The vulnerability does not require user interaction, so no tap, prompt, or pairing consent is needed on the target device.
See the Android Bluetooth Module Update for the upstream patch changing the object lifecycle handling in acl_arbiter.cc.
Detection Methods for CVE-2025-48539
Indicators of Compromise
- Unexpected crashes or tombstoned reports referencing com.android.bluetooth or acl_arbiter.cc in /data/tombstones/.
- Repeated Bluetooth service restarts or bluetoothd process terminations in logcat output.
- Unsolicited ACL connection attempts from unknown Bluetooth MAC addresses in device pairing logs.
Detection Strategies
- Monitor Android device telemetry for abnormal Bluetooth stack crashes correlated with nearby unknown devices.
- Inspect mobile device management (MDM) inventory for devices running Android 15 or 16 without the 2025-09-01 security patch level.
- Correlate Bluetooth scanning activity in enterprise environments with device crash reports to identify targeting attempts.
Monitoring Recommendations
- Enforce reporting of Android ro.build.version.security_patch values through MDM to identify unpatched fleets.
- Alert on repeated Bluetooth process crashes across multiple managed devices in the same physical location.
- Log and review Bluetooth pairing and discovery events on high-value mobile assets.
How to Mitigate CVE-2025-48539
Immediate Actions Required
- Apply the September 2025 Android security patch (patch level 2025-09-01 or later) to all Android 15 and Android 16 devices.
- Disable Bluetooth on devices that cannot be patched, especially in untrusted physical environments.
- Restrict device discoverability and unpair unknown or unused Bluetooth peers.
Patch Information
Google published the fix in the Android Security Bulletin September 2025. The corresponding source change is available in commit c881220f499edcbdff9a7efdf00beeaeba084245 of the Android Bluetooth module. Device vendors must integrate this patch into their monthly security releases and push updates to end users.
Workarounds
- Keep Bluetooth turned off when not actively in use, particularly in public or high-risk locations.
- Configure enterprise policies that disable Bluetooth on managed devices until the September 2025 patch level is confirmed.
- Avoid accepting pairing requests from unknown devices and remove stale bonded devices from the paired list.
# Verify the Android security patch level on a device via adb
adb shell getprop ro.build.version.security_patch
# Expected output for patched devices: 2025-09-01 or later
# Enterprise policy: disable Bluetooth until patched (Android Enterprise)
# Set the following restriction via your MDM:
# disallow_config_bluetooth = true
# disallow_bluetooth = true
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
