CVE-2025-53966: Samsung Exynos Buffer Overflow Vulnerability

CVE-2025-53966 Overview

CVE-2025-53966 is a buffer overflow vulnerability affecting multiple Samsung Exynos mobile processors. The flaw stems from incorrect handling of the NL80211 vendor command during processing of an IOCTL message. An attacker with local access to an affected device can trigger the overflow to corrupt kernel memory. Successful exploitation impacts confidentiality, integrity, and availability of the device. The vulnerability is tracked under CWE-120: Buffer Copy without Checking Size of Input and affects Samsung Exynos 1380, 1480, 1580, and 2400 processors used in modern Android smartphones.

Critical Impact

A local attacker can corrupt kernel memory through a malformed NL80211 vendor command, potentially leading to privilege escalation or arbitrary code execution within the wireless subsystem.

Affected Products

• Samsung Exynos 1380 and 1380 Firmware
• Samsung Exynos 1480 and 1480 Firmware
• Samsung Exynos 1580 and 1580 Firmware
• Samsung Exynos 2400 and 2400 Firmware

Discovery Timeline

• 2026-01-05 - CVE-2025-53966 published to the National Vulnerability Database
• 2026-01-09 - Last updated in NVD database

Technical Details for CVE-2025-53966

Vulnerability Analysis

The vulnerability resides in the wireless networking stack of affected Samsung Exynos processors. Specifically, the NL80211 vendor command path fails to correctly validate or bound input data when processing an IOCTL message. The NL80211 interface is the Netlink protocol used by the Linux kernel to communicate with userspace about 802.11 wireless operations. When the driver processes a vendor-specific command, insufficient size checking allows attacker-controlled data to overflow a fixed-size buffer.

Because the vulnerable code path executes within the kernel context of the baseband or wireless driver, memory corruption directly impacts kernel state. The attack vector is local, which on mobile devices typically means a malicious application or compromised process must be present on the device.

Root Cause

The root cause is improper bounds checking when copying caller-supplied data during NL80211 vendor command handling. The driver assumes the supplied length is within an expected range and writes the payload into a buffer without enforcing the destination size, satisfying the conditions described in CWE-120.

Attack Vector

Exploitation requires local access to the device. An attacker delivers a crafted IOCTL message containing a malformed NL80211 vendor command structure. Processing this message triggers the buffer overflow in the wireless driver, allowing the attacker to overwrite adjacent kernel memory. A skilled attacker can chain this primitive with kernel exploitation techniques to escalate privileges, persist malicious code, or pivot from a sandboxed application to full device compromise. No user interaction is required once the malicious process executes on the device.

No public proof-of-concept exploit has been disclosed at the time of publication, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2025-53966

Indicators of Compromise

• Unexpected crashes or kernel panics in the wireless driver subsystem on Exynos-based devices
• Abnormal NL80211 Netlink traffic originating from unprivileged applications
• Unsigned or unauthorized applications issuing low-level IOCTL calls to wireless interfaces

Detection Strategies

• Monitor mobile device telemetry for repeated wireless driver faults or watchdog resets
• Review mobile application behavior for processes invoking raw socket or Netlink operations without legitimate business justification
• Correlate device crash reports with installation of recently sideloaded or untrusted applications

Monitoring Recommendations

• Enable mobile threat defense logging for applications interacting with low-level system interfaces
• Centralize Android logcat and dmesg captures from managed devices for offline analysis
• Track firmware and security patch level (ro.build.version.security_patch) across the fleet to identify unpatched Exynos devices

How to Mitigate CVE-2025-53966

Immediate Actions Required

• Apply the Samsung security update for affected Exynos processors as soon as it is delivered through the device OEM channel
• Inventory mobile devices to identify those running Exynos 1380, 1480, 1580, or 2400 silicon
• Restrict installation of applications from untrusted sources on impacted devices via mobile device management policy
• Review and remove applications that request access to low-level networking or system interfaces without justification

Patch Information

Samsung has acknowledged the issue through its Semiconductor Product Security Updates program. Refer to the Samsung CVE-2025-53966 Advisory and the Samsung Product Security Updates portal for the latest firmware information. Device-level patches are distributed by Samsung Mobile and partner OEMs as part of monthly Android security bulletins.

Workarounds

• Enforce strict application allow-listing on managed devices until patches are deployed
• Disable Wi-Fi when not required on high-risk devices to reduce exposure to the wireless driver code path
• Apply mobile device management policies that block sideloading and require Google Play Protect to remain enabled

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