CVE-2023-53830: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53830 is a memory leak vulnerability in the Linux kernel's platform/x86: think-lmi driver, specifically in the current_value_show() function. When retrieving an item string via tlmi_setting(), malformed item strings are not freed with kfree() due to an early return path, resulting in a kernel memory leak. The vulnerability affects Linux kernel versions from 5.14 up to the patched releases (5.15.107, 6.1.24, 6.2.11, and 6.3). It was published on December 9, 2025, with an estimated CVSS severity of Medium and an EPSS score of 0.000180 (Feedly, EUVD).

The root cause is a missing kfree() call on the result of tlmi_setting() when the function encounters a malformed item string and takes an early return path in current_value_show() within the think-lmi platform driver (CWE-401: Missing Release of Memory after Effective Lifetime). The think-lmi driver interfaces with Lenovo ThinkPad firmware settings via WMI, and the leak occurs in the sysfs attribute read path. The fix eliminates the early return to ensure the allocated string is always freed regardless of whether the item string is well-formed or malformed (Feedly, EUVD).

The primary impact is a kernel memory leak, which over time can degrade system stability and availability by exhausting kernel memory resources. This vulnerability does not directly enable remote code execution, privilege escalation, or data exfiltration, but repeated triggering of the leak (e.g., by repeatedly reading the affected sysfs attribute) could contribute to denial-of-service conditions on affected systems. The scope is limited to systems running affected Linux kernel versions on Lenovo ThinkPad hardware with the think-lmi driver loaded (Feedly).

The Linux kernel project has released patches addressing this vulnerability in stable branches: versions 5.15.107, 6.1.24, 6.2.11, and 6.3. Administrators should update to these or later kernel versions. The fix is applied via commits to the stable kernel trees (e.g., 5f99014c19fa, b9396d991abe, 9071525bfcb1, a3c4c0530145). As a temporary workaround on systems where the think-lmi driver is not required, the module can be blacklisted to prevent loading (EUVD).