CVE-2023-54191: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-54191 is a memory leak vulnerability in the Linux kernel's WiFi driver subsystem, specifically in the mt7996_mcu_exit routine of the mt76 driver for MediaTek MT7996 wireless chipsets. The flaw causes MCU SKB (socket buffer) queues to not be purged when mt7996_firmware_state fails, resulting in a memory leak. It affects Linux kernel versions from the introduction of the mt7996 driver (commit 98686cd21624) up to the fixes applied in the 6.2.x and 6.3 stable series. The vulnerability was published on December 30, 2025, with a CVSS base score of 0.0 as assessed by ENISA, reflecting its low exploitability and limited direct security impact (Feedly, EUVD).

The root cause is a missing cleanup path in the mt7996_mcu_exit function within the Linux kernel's drivers/net/wireless/mediatek/mt76/mt7996/mcu.c. When mt7996_firmware_state returns a failure, the function exits early without purging the MCU SKB queues, classified as CWE-401 (Missing Release of Memory after Effective Lifetime). The fix ensures that the SKB queue purge is always executed regardless of the return value of mt7996_firmware_state, preventing the memory leak on error paths. Patches were applied to two stable branches: commit b539d35e13e5 (6.2.x series) and commit da5b4d93e141 (6.3 series) (Feedly, EUVD).

The vulnerability results in a kernel memory leak within the WiFi driver subsystem, which can gradually exhaust kernel memory resources on systems using MediaTek MT7996 wireless hardware. This primarily affects availability — repeated triggering of the error path could degrade system performance or contribute to resource exhaustion over time. There is no known direct impact on confidentiality or integrity, and the vulnerability does not enable remote code execution or privilege escalation (Feedly).

The fix has been applied to the Linux kernel stable branches via commits b539d35e13e5 (6.2.x series, patched at 6.2.3) and da5b4d93e141 (6.3 series). Users running affected kernel versions with MediaTek MT7996 WiFi hardware should update to Linux kernel 6.2.3 or later, or 6.3 or later. Linux distributions shipping affected kernel versions should apply the relevant stable kernel updates. No configuration-based workaround is available beyond avoiding use of the affected driver (EUVD).