CVE-2023-54301: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-54301 is a resource leak vulnerability in the Linux kernel's 8250_bcm7271 serial driver, specifically within the brcmuart_probe() function. The flaw causes the baud_mux_clk clock resource obtained via clk_prepare_enable() to not be released on certain error paths (line 1032 of drivers/tty/serial/8250/8250_bcm7271.c). It affects Linux kernel versions starting from commit 41a469482de2 up to the fixes introduced in stable releases 5.15.113, 6.1.30, 6.3.4, and 6.4. The vulnerability was published on December 30, 2025, with a CVSS base score of 0.0 (no severity rating assigned) and an EPSS score of 0.000180 (Feedly, ENISA EUVD).

The root cause is a missing resource release on an error path in the brcmuart_probe() function of the BCM7271 8250 UART driver (CWE-401: Missing Release of Memory after Effective Lifetime). When clk_prepare_enable() is called to enable baud_mux_clk and a subsequent error occurs at line 1032, the clock is not properly released before the function returns, resulting in a kernel resource leak. The fix converts the clock management to use a managed (devm) clock, which ensures automatic cleanup when the device is unbound or probe fails. This was identified by the Smatch static analysis tool (Feedly, ENISA EUVD).

The vulnerability results in a kernel resource leak — specifically, a clock resource that is not freed on certain error paths during driver probe. This is a local, low-severity issue that could contribute to resource exhaustion on affected embedded systems using the BCM7271 UART hardware (common in Broadcom-based set-top box and media platforms). There is no known path to privilege escalation, code execution, or data exposure from this vulnerability; the primary impact is on system availability through gradual resource depletion (Feedly).

The fix is included in Linux kernel stable releases 5.15.113, 6.1.30, 6.3.4, and 6.4, where the clock management in brcmuart_probe() was converted to use a managed (devm) clock to ensure automatic resource cleanup. Users running affected kernel versions on systems with BCM7271 UART hardware should update to a patched stable release. No configuration-based workarounds are available; upgrading the kernel is the recommended remediation (ENISA EUVD, Kernel Patch 5.15).