CVE-2023-53842: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53842 is a resource leak vulnerability in the Linux kernel's ASoC (Audio System on Chip) subsystem, specifically in the wcd-mbhc-v2 codec driver. The flaw causes MBHC (Multi-Button Headset Control) resources to not be properly released on component probe failure or removal, leading to interrupt flag mismatches and initialization failures on reprobing. It affects Linux kernel versions from 5.14 up to (but not including) the patched releases: 5.15.123, 6.1.42, 6.4.7, and 6.5. The vulnerability was published on December 9, 2025, and carries an estimated CVSS severity of Medium with an EPSS score of 0.00018 (Feedly, EUVD).

The root cause is improper resource management (CWE-772: Missing Release of Resource after Effective Lifetime) in the wcd-mbhc-v2 ASoC codec driver. MBHC interrupt resources are tied to the lifetime of the component device rather than being explicitly released on component removal or probe failure. When the sound card fails to instantiate (e.g., returning -EPROBE_DEFER), the interrupt resources remain registered; on reprobing, the kernel's genirq subsystem detects a flags mismatch for the already-registered IRQ (e.g., IRQ 299, mbhc sw intr), returning -EBUSY and preventing successful codec initialization. The fix ensures MBHC resources are explicitly freed during both probe failure and component removal paths (Feedly, Kernel Patch).

The primary impact is a denial of availability for audio subsystem functionality on affected devices. When triggered, the codec component fails to initialize, preventing the sound card from being instantiated and rendering audio hardware non-functional. This affects systems using Qualcomm WCD938x or similar codecs (e.g., Snapdragon SC8280XP-based platforms). There is no known confidentiality or integrity impact, and the vulnerability does not enable privilege escalation or remote code execution (Feedly).

The fix is included in Linux kernel stable releases 5.15.123, 6.1.42, 6.4.7, and 6.5. Users should update to these or later kernel versions. The patches are available via the upstream stable kernel tree at the following commits: 90ab6446eb52 (5.15.x), 17feff71d06c (6.1.x), ce4059e1c0ac (6.4.x), and a5475829adcc (mainline/6.5). Distribution-specific updates (e.g., SUSE) have also been released incorporating these fixes (Feedly, EUVD).