CVE-2025-27052: Qualcomm AR8035 Buffer Overflow Flaw

CVE-2025-27052 Overview

CVE-2025-27052 is a memory corruption vulnerability affecting a broad range of Qualcomm chipset firmware. The flaw resides in the diagnostic (diag) subsystem, which processes data packets received from Unix domain socket clients. A local attacker with low privileges can send crafted packets to the diag interface to trigger a buffer overflow condition [CWE-120], corrupting adjacent memory. Successful exploitation can result in arbitrary code execution in a privileged context, information disclosure, or denial of service. The vulnerability affects Snapdragon mobile, automotive, compute, wearable, IoT, and connectivity platforms across hundreds of Qualcomm SoCs.

Critical Impact
Local, low-privileged attackers can corrupt kernel-adjacent memory through the diag interface, compromising confidentiality, integrity, and availability of Qualcomm-based devices.

Affected Products

Qualcomm Snapdragon mobile platforms (Snapdragon 8 Gen 1/2/3, 8+ Gen 2, 4 Gen 1, 460, 480, 662, 680, 685, 695)
Qualcomm automotive and IoT platforms (SA8155P, SA8255P, SA8295P, SA8775P, QCS series, SRV1H/L/M)
Qualcomm FastConnect, WCN, WCD, WSA, and QCA connectivity firmware families

Discovery Timeline

2025-07-08 - CVE-2025-27052 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-27052

Vulnerability Analysis

The vulnerability is a classic buffer overflow [CWE-120] in the Qualcomm diag (diagnostic) subsystem. The diag driver exposes a Unix domain socket interface that lets user-space clients submit diagnostic command packets to the kernel-mode handler. When the handler parses attacker-influenced fields from an incoming packet, it copies data into a fixed-size buffer without adequately validating length or type boundaries. The resulting out-of-bounds write corrupts adjacent kernel or driver structures.

Because the diag service runs with elevated privileges on Snapdragon devices, memory corruption in this path can be leveraged to escalate privileges from a low-privileged local process to kernel context. The attack requires no user interaction and operates entirely on the local device.

Root Cause

The root cause is missing or insufficient bounds checking on length and content fields of diag command packets received from Unix clients. The handler trusts client-supplied size metadata when copying payload data into a destination buffer, allowing an attacker to overrun the buffer and overwrite adjacent memory.

Attack Vector

Exploitation requires local access to the target device and the ability to open the diag Unix socket. An attacker-controlled process crafts a malformed diagnostic packet with oversized or malformed length fields and writes it to the socket. The diag handler processes the packet, corrupts memory, and, if the overflow is shaped correctly, redirects execution or overwrites security-critical structures. No user interaction is required.

No public proof-of-concept exploit or in-the-wild exploitation has been reported for CVE-2025-27052.

The vulnerability manifests in the diag subsystem packet handler. Refer to the
Qualcomm July 2025 Security Bulletin for handler-level technical details and
the specific driver revision that introduces the bounds-checking fix.

Detection Methods for CVE-2025-27052

Indicators of Compromise

Unexpected crashes, kernel panics, or reboots on Snapdragon-based devices tied to the diag driver or diag-router process
Processes with no legitimate diagnostic role opening the /dev/diag character device or the diag Unix domain socket
Anomalous privilege transitions from unprivileged user processes to system or root context following diag interactions

Detection Strategies

Monitor endpoint telemetry for unusual open, ioctl, or write operations against the diag device node from non-OEM processes
Alert on kernel oops, panic, or dmesg entries referencing the diag driver, buffer overrun signatures, or KASAN reports
Correlate local privilege escalation attempts with prior access to diagnostic interfaces on affected Qualcomm devices

Monitoring Recommendations

Enroll Qualcomm-based endpoints into a mobile threat defense or EDR solution that surfaces kernel crash telemetry and process-to-device access
Baseline which OEM system processes legitimately interact with the diag subsystem and alert on deviations
Ingest device crash and audit logs into a centralized data lake to hunt for repeated diag-adjacent faults across the fleet

How to Mitigate CVE-2025-27052

Immediate Actions Required

Inventory devices using affected Qualcomm chipsets and identify OEM firmware versions currently deployed
Apply OEM firmware updates that incorporate Qualcomm's July 2025 security patch as soon as the vendor makes them available
Restrict which user accounts and applications on managed devices can access the diag interface

Patch Information

Qualcomm addressed CVE-2025-27052 in its July 2025 security bulletin. Device manufacturers must integrate the patched driver into their firmware images and distribute updates to end users. Refer to the Qualcomm July 2025 Security Bulletin for the authoritative list of fixed components and OEM guidance.

Workarounds

Disable or gate access to the diag subsystem on production devices where diagnostic functionality is not required
Enforce mobile device management (MDM) policies that prevent installation of untrusted applications capable of interacting with the diag socket
Where supported by the OEM, remove or restrict permissions on the /dev/diag device node to trusted system users only

bash

# Example: verify diag device node permissions on an affected device
ls -l /dev/diag
# Restrict access to trusted system UIDs only (OEM/root context required)
chmod 600 /dev/diag
chown system:system /dev/diag