CVE-2025-37759: 
Linux Kernel vulnerability analysis and mitigation

A vulnerability in the Linux kernel's ublk (userspace block device) subsystem was discovered and assigned CVE-2025-37759, disclosed on May 1, 2025. The issue relates to improper request reference handling during recovery and reissue operations in the ublkabortqueue() function (NVD, Wiz).

The vulnerability stems from Commit 8284066946e6 which failed to properly grab request reference in case of recovery reissue in the ublkabortqueue() function. When a request is requeued and re-dispatched, it can fail during uring command cancellation. For zero-copy (zc) requests, this can lead to the request being freed before io_uring returns the zc buffer, resulting in a kernel NULL pointer dereference at address 0x00000000000000c8 (Debian Security).

When exploited, this vulnerability results in a kernel panic, causing system instability and potential denial of service. The issue manifests as a supervisor read access error in kernel mode with a NULL pointer dereference, leading to an Oops condition in the Linux kernel (Wiz).

The vulnerability has been fixed by implementing proper request reference handling. The fix involves always grabbing request reference for aborting the request in the ublkabortqueue() function. System administrators are advised to update to kernel versions that include this fix (Wiz).