CVE-2022-50742: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-50742 is a reference count leak vulnerability in the Linux kernel's misc/ocxl (Open Coherent Accelerator Processor Interface) subsystem, specifically within the afu_ioctl() function. The flaw occurs because eventfd_ctx_put() is not called to release the reference obtained by eventfd_ctx_fdget() when ocxl_irq_set_handler() fails, resulting in a resource leak. It affects Linux kernel versions from 5.2 up to (but not including) the patched stable releases. It was published on December 24, 2025, and carries a CVSS v3.1 base score of 5.5 (Medium) (Red Hat CVE, Feedly).

The root cause is a missing reference count decrement (CWE-911: Improper Update of Reference Count) in the afu_ioctl() function of the Linux kernel's OCXL (Open Coherent Accelerator Processor Interface) driver. When ocxl_irq_set_handler() returns an error, the code path fails to invoke eventfd_ctx_put() to release the eventfd context reference previously acquired via eventfd_ctx_fdget(). This results in a reference count leak that can prevent proper resource cleanup. The vulnerability requires local access and low privileges to trigger, as it is reachable through an ioctl call on an OCXL device (Red Hat CVE, EUVD).

The primary impact is an availability issue — the reference count leak can lead to resource exhaustion or improper kernel object lifecycle management, potentially causing system instability or denial of service conditions on affected systems. There is no confidentiality or integrity impact associated with this vulnerability. The scope is limited to the local system, and lateral movement or data exfiltration are not applicable in this context (Red Hat CVE).

The vulnerability has been patched in multiple Linux kernel stable branches. Fixed versions include Linux kernel 5.4.220, 5.10.150, 5.15.75, 5.19.17, 6.0.3, and 6.1 and later. Users should update to the appropriate patched stable kernel release for their distribution. SUSE has also issued kernel security advisories (e.g., SUSE-2026-0263-1, SUSE-2026-0317-1, SUSE-2026-0350-1, SUSE-2026-0411-1) addressing this issue (Red Hat CVE, Linux Security SUSE).