CVE-2025-21424: Qualcomm 315 5G IoT Use-After-Free Flaw

CVE-2025-21424 Overview

CVE-2025-21424 is a memory corruption vulnerability affecting a broad range of Qualcomm chipsets and firmware. The flaw resides in the Neural Processing Unit (NPU) driver and is triggered when NPU driver APIs are called concurrently. The issue is classified as a use-after-free condition [CWE-416] and requires local, low-privilege access to exploit.

Qualcomm disclosed the issue in the Qualcomm March 2025 Security Bulletin. The affected component ships across Snapdragon mobile, automotive, compute, IoT, and connectivity platforms, making the vulnerability relevant to mobile devices, connected vehicles, and embedded systems.

Critical Impact
A local attacker with low privileges can corrupt kernel memory through concurrent NPU driver API calls, resulting in impact to confidentiality, integrity, and availability on affected devices.

Affected Products

Qualcomm Snapdragon mobile platforms including Snapdragon 8 Gen 1/2/3, 8+ Gen 2, 888/888+ 5G, 865/870, and 4 Gen 1
Qualcomm automotive platforms including SA8155P, SA8255P, SA8295P, SA8540P, SA8620P, SA8650P, SA8770P, and SA8775P
Qualcomm IoT, compute, wearable, XR, and FastConnect firmware (QCS, QCM, QCN, QCA, SDX, and WCN series)

Discovery Timeline

2025-03-03 - CVE-2025-21424 published to NVD
March 2025 - Qualcomm publishes the March 2025 Security Bulletin with patch guidance
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-21424

Vulnerability Analysis

The vulnerability is a memory corruption condition in Qualcomm's NPU (Neural Processing Unit) driver. The NPU driver exposes APIs used by higher-level frameworks to submit inference workloads and manage acceleration contexts. When multiple threads invoke these APIs concurrently, the driver mismanages the lifetime of shared kernel objects, leading to a use-after-free condition as tracked by [CWE-416].

Successful exploitation can allow a local, low-privileged attacker to corrupt kernel memory. On mobile and automotive SoCs, this can undermine process isolation between user applications and privileged system services. The attack requires local access and no user interaction.

Root Cause

The root cause is insufficient synchronization within the NPU driver's API entry points. Concurrent invocations race against object allocation, reference counting, or teardown routines. A thread continues to reference kernel memory after another thread has freed it, producing a classic use-after-free primitive that an attacker can shape into memory corruption.

Attack Vector

Exploitation requires code execution on the device, typically via a malicious application or a compromised system component with permission to invoke NPU driver interfaces. The attacker issues rapid, interleaved NPU driver API calls from multiple threads to trigger the race window. Once the freed object is reallocated with attacker-controlled data, the dangling reference can be leveraged to escalate privileges or destabilize the kernel.

See the Qualcomm March 2025 Security Bulletin for technical details on the affected driver interfaces.

// No verified proof-of-concept is publicly available.
// The vulnerability manifests when concurrent threads
// invoke NPU driver APIs and race against object teardown,
// producing a use-after-free condition (CWE-416).

Detection Methods for CVE-2025-21424

Indicators of Compromise

Unexpected kernel panics, watchdog resets, or NPU subsystem crashes referencing NPU driver modules in device logs
Applications making abnormally high-frequency or highly parallel calls to NPU inference APIs
Kernel dmesg, logcat, or platform ramdump entries indicating use-after-free, slab corruption, or KASAN reports in NPU-related code paths

Detection Strategies

Monitor mobile device management (MDM) and endpoint telemetry for installation of untrusted applications that request access to on-device AI acceleration APIs
Correlate repeated device instability, reboots, or NPU service restarts with recently installed or updated applications
Track firmware and patch level compliance against the March 2025 Qualcomm security patch baseline across mobile, automotive, and IoT fleets

Monitoring Recommendations

Ingest Android and vendor-specific device logs into a centralized logging or SIEM platform to spot kernel-side anomalies
Alert on devices reporting Qualcomm patch levels older than March 2025
For automotive and IoT deployments, monitor Qualcomm platform diagnostics for repeated NPU driver faults

How to Mitigate CVE-2025-21424

Immediate Actions Required

Apply the Qualcomm-supplied firmware update referenced in the March 2025 Security Bulletin to all affected Snapdragon, SA-series, QCS, QCM, QCN, and related platforms
Coordinate with OEMs and Tier-1 vendors to obtain and deploy the corresponding device-level patches for handsets, vehicles, and IoT hardware
Restrict installation of untrusted third-party applications on affected devices until patching is complete

Patch Information

Qualcomm addressed the issue in the March 2025 security patch level. Consult the Qualcomm March 2025 Security Bulletin for the definitive list of affected chipsets and fixed firmware versions. Downstream OEMs must integrate the fix into device firmware and distribute over-the-air updates.

Workarounds

No official workaround has been published by Qualcomm; patching is the required remediation
Enforce application allowlisting and vet apps requesting access to on-device AI/NPU acceleration frameworks
Where feasible, disable or restrict access to NPU-dependent features on unpatched devices in sensitive environments

bash

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

# Confirm the reported patch level is 2025-03-01 or later
# For automotive/IoT platforms, verify firmware version against
# the Qualcomm March 2025 Security Bulletin.