CVE-2025-21474: Qualcomm Fastconnect Use-After-Free Flaw

CVE-2025-21474 Overview

CVE-2025-21474 is a use-after-free memory corruption vulnerability [CWE-416] affecting Qualcomm Bluetooth firmware components. The flaw resides in the Advanced Audio Distribution Profile (A2DP) sink command queue processing logic. An authenticated local attacker with low privileges can trigger the condition to corrupt memory within the Bluetooth stack. Successful exploitation can lead to arbitrary code execution, information disclosure, or a denial-of-service condition on the affected chipset. The vulnerability impacts a broad range of Qualcomm Snapdragon mobile, automotive, wearable, and IoT platforms. Qualcomm disclosed the issue in its August 2025 Security Bulletin.

Critical Impact
Local exploitation can compromise confidentiality, integrity, and availability on affected Snapdragon and FastConnect chipsets embedded in mobile phones, automotive systems, wearables, and IoT devices.

Affected Products

Qualcomm FastConnect 6800, 6900, and 7800 firmware
Qualcomm Snapdragon 8 Gen 1, 865/865+/870 5G, W5+ Gen 1, XR2 5G, and X55 5G Modem-RF platforms
Qualcomm QCA/QCN/QCS series, SA-series automotive SoCs, WCN Bluetooth radios, and WCD/WSA audio codecs

Discovery Timeline

2025-08-06 - CVE-2025-21474 published to the National Vulnerability Database (NVD)
August 2025 - Qualcomm publishes the Qualcomm Security Bulletin August 2025
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-21474

Vulnerability Analysis

The vulnerability is a use-after-free condition [CWE-416] in the Bluetooth A2DP sink command queue handler. A2DP is the Bluetooth profile responsible for streaming stereo audio between devices such as headphones, speakers, and infotainment systems. When the firmware processes commands from the A2DP sink queue, an object referenced by the queue can be freed while a dangling pointer to it remains in use. Subsequent dereferences of that stale pointer corrupt memory in the Bluetooth controller's address space.

Because the affected code runs inside a privileged firmware context on the wireless SoC, memory corruption there can cascade into the host operating system through shared transport buffers or IPC channels.

Root Cause

The root cause is improper lifetime management of A2DP sink command objects. The firmware releases a command structure without invalidating references held by concurrent processing paths. The remaining stale reference is later dereferenced, producing a classic use-after-free primitive that an attacker can shape into a write-what-where or control-flow hijack.

Attack Vector

Exploitation requires local access with low privileges and no user interaction. An attacker with the ability to invoke Bluetooth-related interfaces or influence A2DP sink command flow can trigger the freed-object reuse. On mobile platforms this typically maps to a compromised application with Bluetooth permissions. On automotive and IoT platforms it maps to any process with access to the Bluetooth HCI or vendor command interface. The Qualcomm advisory does not list this issue as exploited in the wild, and no public proof-of-concept is available.

No verified proof-of-concept code has been published for CVE-2025-21474.
Refer to the Qualcomm August 2025 Security Bulletin for advisory-level detail.

Detection Methods for CVE-2025-21474

Indicators of Compromise

Unexpected Bluetooth stack crashes, kernel panics, or bluetoothd restarts on devices with a Qualcomm wireless SoC
Firmware coredumps or ramdumps referencing A2DP sink command processing paths
Abnormal HCI transport errors or watchdog resets on the Bluetooth subsystem shortly after audio-profile activity

Detection Strategies

Correlate Bluetooth subsystem crash logs (logcat, dmesg, vendor ssr_dump) with sequences of A2DP sink connection or command activity from untrusted peer devices or local apps.
Monitor for local processes that hold BLUETOOTH_CONNECT or vendor-specific Bluetooth privileges and interact with A2DP profiles outside expected application behavior.
Track firmware and patch level compliance across the fleet against the Qualcomm August 2025 Security Bulletin baseline.

Monitoring Recommendations

Ingest mobile and IoT device telemetry, including Bluetooth stack logs, into a centralized analytics platform for anomaly detection.
Alert on repeated Bluetooth subsystem restarts or A2DP session terminations that correlate with a single application or peer MAC address.
Include Qualcomm patch level and OEM security patch date in device posture checks used for conditional access decisions.

How to Mitigate CVE-2025-21474

Immediate Actions Required

Inventory all Qualcomm-based devices in your environment against the affected chipset list in the Qualcomm August 2025 Security Bulletin.
Apply OEM firmware updates that incorporate the August 2025 Qualcomm patch as soon as they are released for each device model.
Restrict installation of untrusted third-party applications on affected mobile and IoT endpoints until patches are deployed.

Patch Information

Qualcomm addressed CVE-2025-21474 in the Qualcomm Security Bulletin August 2025. Fixes are distributed to Original Equipment Manufacturers (OEMs), who must integrate them into device-specific firmware and ship them through their standard update channels. Verify remediation by confirming the vendor security patch level on each device meets or exceeds August 2025.

Workarounds

Disable Bluetooth on affected devices when audio streaming or peripheral connectivity is not required.
Avoid pairing with untrusted A2DP sinks or sources, and remove unused Bluetooth pairings.
On managed fleets, use Mobile Device Management (MDM) policies to restrict Bluetooth usage on devices that cannot yet receive the August 2025 patch level.

bash

# Example: query Android security patch level to validate remediation
adb shell getprop ro.build.version.security_patch
# Expected: 2025-08-01 or later for devices carrying the Qualcomm August 2025 fix