CVE-2026-21375: Qualcomm Cologne Buffer Overflow Flaw

CVE-2026-21375 Overview

CVE-2026-21375 is a memory corruption vulnerability affecting multiple Qualcomm chipset firmware products. The flaw occurs during IOCTL (Input/Output Control) processing when the affected driver accesses an output buffer without properly validating its size. This out-of-bounds read vulnerability (CWE-126) allows a local attacker with low privileges to potentially achieve complete system compromise, including unauthorized data access, system modification, and service disruption.

Critical Impact

Local attackers can exploit improper buffer size validation during IOCTL processing to corrupt memory, potentially leading to privilege escalation, arbitrary code execution, or system instability on affected Qualcomm-based devices.

Affected Products

• Qualcomm Snapdragon 460 Mobile Platform Firmware
• Qualcomm Snapdragon 662 Mobile Platform Firmware
• Qualcomm Snapdragon 7c+ Gen 3 Compute Firmware
• Qualcomm Snapdragon 8cx Gen 3 Compute Platform Firmware
• Qualcomm FastConnect 6700/6900/7800 Firmware
• Qualcomm QCM5430 and QCM6490 Firmware
• Qualcomm Video Collaboration VC3 Platform Firmware
• Qualcomm WCD9370/9375/9378c/9380/9385 Audio Codec Firmware
• Qualcomm WCN3950/3988 WiFi Chipset Firmware
• Qualcomm WSA8830/8832/8835/8840/8845/8845h Speaker Amplifier Firmware

Discovery Timeline

• April 6, 2026 - CVE-2026-21375 published to NVD
• April 8, 2026 - Last updated in NVD database

Technical Details for CVE-2026-21375

Vulnerability Analysis

This vulnerability stems from a buffer over-read condition (CWE-126) in the IOCTL handler within affected Qualcomm firmware components. When processing IOCTL requests, the driver fails to validate the size of the output buffer before accessing it, leading to potential memory corruption.

The attack requires local access to the system with low privileges. Once an attacker gains the ability to interact with the vulnerable driver through IOCTL system calls, they can craft malicious requests that cause the driver to read beyond the bounds of allocated memory regions. This can expose sensitive kernel memory contents or trigger memory corruption that could be leveraged for further exploitation.

The impact of successful exploitation is significant, as it can lead to complete compromise of confidentiality, integrity, and availability on the affected device. Given that Qualcomm chipsets power a vast array of mobile devices, laptops, and IoT products, this vulnerability presents a substantial attack surface across the consumer and enterprise device ecosystem.

Root Cause

The root cause of CVE-2026-21375 is improper input validation in the IOCTL processing code path. Specifically, the firmware fails to verify that the provided output buffer is large enough to safely receive the requested data before writing to it. This missing bounds check allows memory operations to exceed the intended buffer boundaries.

In typical secure IOCTL implementations, the driver should validate both the input and output buffer sizes against expected minimums before performing any operations. The absence of this validation creates a condition where user-controlled parameters can influence memory access patterns in unintended ways.

Attack Vector

The attack vector for CVE-2026-21375 is local, requiring an attacker to have authenticated access to the target system with low privileges. The exploitation scenario involves:

1. An attacker identifies a device running vulnerable Qualcomm firmware
2. The attacker crafts a malicious IOCTL request with manipulated buffer parameters
3. The request is sent to the vulnerable driver interface
4. The driver processes the request without proper size validation
5. Memory corruption or information disclosure occurs as a result

The attack does not require user interaction and has an unchanged scope, meaning the impact is confined to the vulnerable component's security context. However, the potential for privilege escalation through memory corruption could allow an attacker to escape this boundary.

Detection Methods for CVE-2026-21375

Indicators of Compromise

• Unusual IOCTL call patterns to Qualcomm driver interfaces, particularly with abnormal buffer size parameters
• System crashes or kernel panics associated with Qualcomm driver components
• Evidence of privilege escalation attempts following driver interactions
• Memory access violations in kernel logs related to audio, WiFi, or platform firmware modules

Detection Strategies

• Implement kernel-level monitoring to detect suspicious IOCTL system calls targeting Qualcomm driver interfaces
• Deploy endpoint detection and response (EDR) solutions capable of identifying memory corruption exploitation patterns
• Monitor for abnormal driver behavior including unexpected memory allocation patterns
• Use SentinelOne's behavioral AI engine to detect exploitation attempts based on process behavior anomalies

Monitoring Recommendations

• Enable verbose logging for device driver interactions on systems with affected Qualcomm hardware
• Implement runtime integrity monitoring for kernel memory regions
• Deploy mobile device management (MDM) solutions with firmware version tracking capabilities
• Configure alerts for system stability issues that may indicate exploitation attempts

How to Mitigate CVE-2026-21375

Immediate Actions Required

• Identify all devices in your environment using affected Qualcomm chipsets and firmware versions
• Apply firmware updates from Qualcomm and device manufacturers as they become available
• Implement additional access controls to limit which users and processes can interact with driver interfaces
• Monitor affected systems for signs of exploitation while awaiting patches

Patch Information

Qualcomm has addressed this vulnerability in their April 2026 Security Bulletin. Organizations should apply firmware updates through their device manufacturers' standard update channels. The security bulletin is available at the Qualcomm April 2026 Security Bulletin.

For mobile devices, firmware updates are typically delivered through OEM-specific update mechanisms. Enterprise administrators should work with device vendors to prioritize deployment of security patches addressing CVE-2026-21375.

Workarounds

• Restrict local user access on affected devices to reduce the attack surface for exploitation
• Implement application allowlisting to prevent unauthorized programs from interacting with vulnerable driver interfaces
• Deploy SentinelOne endpoint protection to detect and block exploitation attempts at runtime
• Consider network segmentation for IoT devices running affected Qualcomm firmware to limit potential lateral movement

# Verify Qualcomm firmware version on Android devices
adb shell getprop ro.board.platform
adb shell getprop ro.build.version.security_patch

# Check for vulnerable driver modules (Linux-based systems)
lsmod | grep -i qualcomm
cat /sys/module/*/version 2>/dev/null | head -20