In the Linux kernel the null_blk module can leak memory and kernel resources when its initialization fails. During boot the module allocates a global tag_set for block I/O tagging. If the subsequent device creation fails, the cleanup routine improperly omits freeing this global tag_set, resulting in a permanent memory leak. The leaked tag_set occupies kernel memory and its internal maps, which can grow unbounded over time and degrade system performance or lead to a complete memory exhaustion, effectively causing a denial of service.

The vulnerability is present in the Linux kernel, affecting all distributions that ship a kernel module named null_blk. No specific kernel version range is listed in the advisory, so kernels prior to the patch referenced in the advisory are considered affected.

The EPSS score is less than 1 % and the vulnerability is not listed in the CISA KEV catalog, indicating a low probability of exploitation in the wild. The exploitation requires code executed in kernel mode, typically as a local privileged attacker or a malicious module loader. The primary risk is a local denial of service; remotely-triggered exploitation would be limited by the need for kernel module loading privileges.