CVE-2026-72225

A flaw was found in the Linux kernel's jbd2 journaling layer. An integer underflow vulnerability in the jbd2_journal_initialize_fast_commit() function occurs when validating journal capacity. This underflow can corrupt critical journal metadata, such as j_last, j_fc_first, and j_free, leading to a journal abort. This issue can result in a Denial of Service (DoS) for the affected system.

Red Hat has rated this vulnerability as Low impact because exploitation requires the ability to mount a maliciously crafted filesystem or directly manipulate raw block device data, privileges restricted to administrative users in standard configurations. The fast commit journal capability involved in this underflow is an optional feature that is not enabled by default on standard ext4 filesystems. Furthermore, triggering the condition causes an internal journal abort resulting in a filesystem-level denial of service rather than code execution or broader system compromise.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.