CVE-2025-21481: Qualcomm 315 5G IoT Buffer Overflow Flaw

CVE-2025-21481 Overview

CVE-2025-21481 is a memory corruption vulnerability in Qualcomm firmware that occurs while performing private key encryption operations within a trusted application. The flaw is categorized as a buffer copy without checking the size of input [CWE-120] and affects an extensive range of Qualcomm chipsets spanning mobile, compute, automotive, IoT, wearable, and networking platforms. A local attacker with low privileges can trigger the condition to corrupt memory in a security-sensitive execution context and impact confidentiality, integrity, and availability.

Critical Impact
Memory corruption in a trusted application handling private key encryption can undermine cryptographic boundaries, enabling privilege escalation or compromise of key material on affected Qualcomm devices.

Affected Products

Qualcomm Snapdragon mobile platforms including Snapdragon 8 Gen 1, 8 Gen 3, 888, 865, 855, and 780G
Qualcomm Snapdragon compute, automotive (SA-series), XR, and wearable (W5+ Gen 1) platforms
Qualcomm FastConnect, QCA connectivity, WCN, WCD, and QCN networking and audio firmware

Discovery Timeline

2025-09-24 - CVE-2025-21481 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-21481

Vulnerability Analysis

The vulnerability resides in a Qualcomm trusted application that performs private key encryption. During processing, the code copies data into a buffer without correctly validating the size of the input, corresponding to CWE-120 (Classic Buffer Overflow). Because the affected routine runs inside a trusted execution environment component that handles cryptographic material, memory corruption in this path has consequences beyond a typical userspace overflow. Successful exploitation requires local access with low privileges and no user interaction, and can result in full compromise of confidentiality, integrity, and availability on the affected device.

Root Cause

The root cause is missing or insufficient bounds checking during a buffer copy operation invoked while the trusted application performs private key encryption. Input controlled by a lower-privileged caller reaches a fixed-size destination buffer without a proper length comparison, permitting adjacent memory to be overwritten.

Attack Vector

Exploitation is local. An attacker with the ability to execute code on the device and invoke the affected trusted-application interface can supply crafted input that triggers the out-of-bounds write. Because the flaw affects a component that operates on private keys within a trusted environment, corrupted state may influence cryptographic outputs or control flow inside a privileged security boundary.

// No public proof-of-concept or exploit code is available for CVE-2025-21481.
// Refer to the Qualcomm September 2025 Security Bulletin for vendor details.

Detection Methods for CVE-2025-21481

Indicators of Compromise

Unexpected crashes, resets, or watchdog events attributed to the trusted-application or QSEE/TEE subsystem on affected Qualcomm devices
Anomalous invocations of key management or cryptographic services from unprivileged processes on the device

Detection Strategies

Monitor device firmware and OEM security patch level against the Qualcomm September 2025 Security Bulletin baseline to identify unpatched hardware.
Review vendor-supplied kernel and TEE logs for abnormal termination of trusted applications performing cryptographic operations.

Monitoring Recommendations

Track OEM firmware update rollouts across mobile, automotive, and IoT fleets to confirm the Qualcomm patch has been applied.
Alert on repeated failures or crashes originating from trusted-application interfaces used for private key operations.

How to Mitigate CVE-2025-21481

Immediate Actions Required

Apply firmware updates from device OEMs that incorporate Qualcomm's September 2025 security bulletin fixes as soon as they are made available.
Inventory affected Qualcomm chipsets across mobile, compute, automotive, wearable, and IoT deployments and prioritize devices exposed to untrusted applications.
Restrict installation of untrusted third-party applications on affected devices until patches are deployed.

Patch Information

Qualcomm has published fixes as part of the Qualcomm Security Bulletin September 2025. Patches are delivered to end users through downstream device OEMs and carriers as part of firmware updates for the affected Snapdragon, QCA, QCN, QCS, SA, WCD, WCN, and related product families.

Workarounds

No vendor-supplied workaround is documented; installing the OEM firmware update that incorporates the Qualcomm patch is the required remediation.
Reduce local attack surface by limiting sideloading and enforcing application allow-listing on affected endpoints until updates are applied.

bash

# Example: check Android security patch level to validate that
# device firmware includes the September 2025 Qualcomm bulletin fixes
adb shell getprop ro.build.version.security_patch
adb shell getprop ro.vendor.build.security_patch