CVE-2023-53108: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53108 is a vulnerability discovered in the Linux kernel's Inter-User Communication Vehicle (IUCV) module, disclosed on May 2, 2025. The vulnerability specifically affects the net/iucv module on z/VM environments, where the iucvirqdata structure requires an additional 4 bytes to properly handle data written by the z/VM hypervisor during CPU deconfiguration (NVD, Wiz Report).

The vulnerability manifests as a kmalloc Redzone overwrite bug in the dma-kmalloc-64 slab. When the z/VM hypervisor writes data during CPU deconfiguration, the allocated buffer proves insufficient, resulting in a buffer overflow condition. At offset 1380, the first byte 0x80 overwrites the expected 0xcc value. The vulnerability has received a CVSS 3.1 base score rating of 5.5 with the vector string AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (Red Hat).

When exploited, this vulnerability can lead to memory corruption in the Linux kernel's IUCV (Inter-User Communication Vehicle) module. The primary impact is on system stability and security specifically in z/VM environments (Wiz Report).

The vulnerability has been fixed in multiple Linux distributions through security updates. Debian has released fixes in versions 5.10.223-1 for bullseye, 6.1.129-1 for bookworm, and 6.12.25-1 for trixie. Red Hat has deferred fixes for Red Hat Enterprise Linux 9 kernel and kernel-rt packages (Debian Tracker, Red Hat).