CVE-2023-53404: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53404 is a memory leak vulnerability in the Linux kernel's USB fotg210 driver, caused by improper use of the debugfs_lookup() function without calling dput() on the returned result. The flaw affects Linux kernel versions before 5.15.100, versions 5.16 through 6.1.17, and versions 6.2 through 6.2.4. It was published on September 18, 2025, and carries a CVSS v3.1 base score of 5.5 (Medium) (Red Hat Advisory, Feedly).

The root cause is classified as CWE-401 (Missing Release of Memory after Effective Lifetime). In the fotg210 USB driver, calls to debugfs_lookup() return a dentry reference that must be released via dput() when no longer needed; omitting this call causes a gradual kernel memory leak. The fix replaces debugfs_lookup() with debugfs_lookup_and_remove(), which atomically handles both the lookup and cleanup in a single call. Exploitation requires local access with low privileges and no user interaction (Feedly, kernel.org patch).

Successful exploitation results in gradual kernel memory exhaustion, degrading system performance and potentially causing resource constraints or denial of service over time. There is no confidentiality or integrity impact — the vulnerability is limited to availability (CVSS A:H). An attacker with local access could repeatedly trigger the memory leak to accelerate resource depletion on affected systems (Feedly).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation at this time. The EPSS score is approximately 0.018%, indicating very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires local access with low privileges, limiting the practical attack surface (Feedly).

Update the Linux kernel to a patched version: 5.15.100 or later (for the 5.15.x stable branch), 6.1.18 or later (for the 6.1.x stable branch), or 6.2.5 or later (for the 6.2.x branch). Patches are available via the upstream kernel stable tree. For systems that cannot be immediately patched, monitor kernel memory usage and limit local user access to reduce exposure (kernel.org patch, Red Hat Advisory).