CVE-2025-21444: Qualcomm Qam8255p Buffer Overflow Flaw

CVE-2025-21444 Overview

CVE-2025-21444 is a memory corruption vulnerability affecting the Ethernet Media Access Controller (EMAC) component across a broad range of Qualcomm automotive and connectivity firmware. The flaw occurs when the EMAC driver copies a result buffer to the transmission queue, leading to memory corruption classified under [CWE-120] (Buffer Copy without Checking Size of Input). Exploitation requires local access with low privileges and no user interaction, and can compromise confidentiality, integrity, and availability on affected devices.

Critical Impact
A local, low-privileged attacker can trigger memory corruption in the EMAC driver, potentially leading to arbitrary code execution or denial of service on Qualcomm automotive and connectivity platforms.

Affected Products

Qualcomm QAM series firmware (QAM8255P, QAM8295P, QAM8620P, QAM8650P, QAM8775P, QAMSRV1H, QAMSRV1M)
Qualcomm QCA series firmware (QCA6574AU, QCA6595, QCA6595AU, QCA6688AQ, QCA6696, QCA6698AQ, QCA6797AQ)
Qualcomm SA and SRV automotive platforms (SA7255P, SA7775P, SA8255P, SA8295P, SA8540P, SA8620P, SA8650P, SA8770P, SA8775P, SA9000P, SRV1H, SRV1L, SRV1M)

Discovery Timeline

2025-07-08 - CVE-2025-21444 published to NVD as part of the Qualcomm July 2025 Security Bulletin
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-21444

Vulnerability Analysis

The vulnerability resides in the EMAC driver logic that handles result buffer transfers into the transmission queue. When the driver copies data returned from a processing operation into the queue, it fails to properly validate the size of the source data relative to the destination buffer. This mismatch enables adjacent memory regions to be overwritten, corrupting driver state or kernel structures.

Because the EMAC component runs in a privileged execution context on affected Qualcomm system-on-chips (SoCs), successful corruption can escalate privileges or destabilize the platform. The affected devices are predominantly used in automotive telematics, in-vehicle infotainment, and connected vehicle platforms, where continuous network availability is required for safety-adjacent functions.

Root Cause

The root cause is an unchecked buffer copy operation, tracked under [CWE-120]. The driver assumes the size of the result buffer is bounded by upstream logic but does not enforce a length check when moving the buffer into the transmission queue. When the source length exceeds the destination capacity, memory adjacent to the queue is overwritten, corrupting kernel-level data structures.

Attack Vector

Exploitation requires local access to the device with low privileges. An attacker running unprivileged code on the affected platform can craft input that reaches the EMAC transmit path and triggers the oversized copy. No user interaction is required, and the attack does not need to cross a trust boundary such as a network interface. Public proof-of-concept code is not available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

No verified exploitation code is publicly available. Refer to the Qualcomm Security Bulletin July 2025 for vendor-provided technical details.

Detection Methods for CVE-2025-21444

Indicators of Compromise

Unexpected kernel panics, watchdog resets, or system crashes referencing the EMAC driver or transmission queue subsystems.
Anomalous processes with local user privileges interacting with EMAC device nodes or /dev entries associated with network interfaces.
Firmware integrity checks failing on affected Qualcomm platforms after suspected local exploitation attempts.

Detection Strategies

Monitor kernel logs and crash dumps for stack traces implicating EMAC transmit paths or heap corruption signatures.
Correlate unprivileged process activity with driver-level errors on automotive gateway and telematics units.
Track firmware version telemetry across fleets to identify devices still running pre-patch builds listed in the Qualcomm advisory.

Monitoring Recommendations

Ingest device telemetry, kernel logs, and firmware version data into a centralized analytics platform for continuous review.
Alert on repeated crashes or reboots of components tied to the EMAC subsystem across a fleet of similar devices.
Maintain an asset inventory mapping affected Qualcomm chipsets to firmware versions to prioritize patch rollout.

How to Mitigate CVE-2025-21444

Immediate Actions Required

Apply the firmware updates published in the Qualcomm Security Bulletin July 2025 through your OEM or platform integrator.
Inventory all deployed devices using the affected QAM, QCA, SA, and SRV series chipsets and confirm firmware versions.
Restrict local access to affected devices, including physical ports, debug interfaces, and unprivileged shell access, until patches are deployed.

Patch Information

Qualcomm addressed CVE-2025-21444 in the July 2025 security bulletin. Patches are distributed through downstream original equipment manufacturers (OEMs) and Tier 1 automotive suppliers. Operators should coordinate with their device vendors to obtain and deploy the firmware release corresponding to their specific chipset.

Workarounds

Limit code execution on affected devices to signed, vetted applications to reduce the local attack surface.
Enforce least-privilege policies so that untrusted processes cannot reach EMAC interfaces or driver ioctls.
Segment automotive and IoT networks to prevent lateral movement from any device that gains local execution.

bash

# Verify firmware version and inventory affected devices (example)
# Consult your OEM documentation for exact commands per platform
cat /proc/version
dmesg | grep -i emac