The Linux kernel’s journaling subsystem includes a jbd2 shrinker that frees checkpoint buffers. The bug causes the shrinker to count only successfully released buffers, ignoring busy ones. When a checkpoint transaction has many busy buffers, the shrinker scans the entire list while holding j_list_lock, which can keep that lock for an extended time, causing producing soft lockups or RCU stall conditions. The root effect is a denial of service in the kernel’s memory management and a degradation of system responsiveness.

The affected software is the Linux kernel, specifically the jbd2 shrinker component. Any kernel version that contains the unpatched jbd2 shrinker logic is vulnerable. Since the vulnerability is catalogued under Linux, it applies to all Linux distributions that ship a kernel containing the bug, regardless of vendor. Affected installations are those running such a kernel prior to the patch being merged.

The CVSS score of 4.7 indicates moderate severity. The EPSS score is less than 1% and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector—based on the description—requires an application that performs heavy journaling activity to create a large checkpoint list, forcing the shrinker to scan many busy buffers while holding the lock. This scenario is local and non‑trivial, necessitating a process that can generate the workload, and it does not provide remote code execution or privilege escalation. Exploitation is therefore possible but requires precise load patterns that may be difficult to produce reliably.