CVE-2023-54300: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-54300 is a vulnerability in the Linux kernel's ath9k Wi-Fi driver that allows uninitialized memory to be referenced in the ath9k_wmi_ctrl_rx() function. The flaw exists in the wifi: ath9k subsystem and affects Linux kernel versions starting from commit fb9987d0f748 up to multiple stable branch fix points. It was discovered by the Linux Verification Center (linuxtesting.org) using Syzkaller and published on December 30, 2025. The CVSS base score is listed as 0.0 (no severity rating assigned at time of publication) (Feedly, EUVD).

The root cause is insufficient input validation (CWE-908: Use of Uninitialized Resource) in the ath9k_wmi_ctrl_rx() endpoint RX handler. When ath9k_htc_rx_msg() receives a socket buffer (SKB) with a small pkt_len (e.g., 8 bytes), the SKB may only contain a valid htc_frame_hdr but not the expected WMI command header in its data payload. Without sanity checking in ath9k_wmi_ctrl_rx(), the function proceeds to reference memory beyond the valid SKB data, accessing uninitialized kernel memory. The fix implements bounds checking inside ath9k_wmi_ctrl_rx() to validate that the SKB payload is large enough to contain a WMI command header before accessing it, mirroring the approach taken in the related commit b383e8abed41 (Feedly, Kernel Git).

Successful exploitation of this vulnerability could allow an attacker to read uninitialized kernel memory, potentially leaking sensitive information such as kernel addresses, cryptographic material, or other data resident in memory. The vulnerability is local in nature and primarily affects systems using Qualcomm Atheros AR9271 802.11n USB Wi-Fi adapters or similar ath9k HTC-based hardware. While the direct impact is an information disclosure risk, uninitialized memory reads in kernel drivers can also contribute to kernel instability or be chained with other vulnerabilities for privilege escalation (Feedly).

The fix has been backported to multiple stable Linux kernel branches. Patched versions include: 4.14.322, 4.19.291, 5.4.251, 5.10.188, 5.15.121, 6.1.39, 6.3.13, 6.4.4, and 6.5+. Users should update their Linux kernel to one of these patched versions. The relevant upstream fix commits are available in the stable kernel tree (Kernel Git). As a workaround, systems that do not use ath9k HTC-based USB Wi-Fi adapters can blacklist the ath9k_htc kernel module to prevent the vulnerable code path from being loaded.