CVE-2026-100073

A flaw was found in the Linux kernel's ext4 file system. When saving modified memory pages back to storage, the system underestimates the journal transaction space required to split and update file block mappings. A local user could exploit this flaw by performing specific write operations, triggering a transaction overflow that leads to a Denial of Service (DoS) through a kernel crash or file system error.

A flaw of moderate severity was found in the Linux kernel's ext4 file system. When dirty pages are written back to storage, the number of journal transaction credits reserved for extent conversion can be underestimated: converting a single large unwritten extent into many smaller written extents (for example, when a large folio is sparsely dirtied) may require splitting extents and allocating new extent tree nodes, which can exceed the reserved credits. A local user with write access to an ext4 file system could exploit this flaw by performing specific write operations that trigger a transaction overflow, resulting in a journal abort, file system error, or kernel crash, and therefore a denial of service.

This issue affects Red Hat Enterprise Linux 10 (kernel) and Red Hat In-Vehicle OS 2 (kernel and kernel-ivos-qualcomm), into which the introducing change was backported. Red Hat Enterprise Linux 7, 8, and 9, including their Real-time kernel variants and Red Hat Enterprise Linux 10.0, are not affected because the vulnerable code is not present in those products; the Red Hat Enterprise Linux CoreOS images shipped with OpenShift Container Platform are likewise not affected. For the affected products, the fix is deferred to a future update. The residual risk is limited to local denial of service: the flaw has no confidentiality or integrity impact and cannot be triggered without local write access to an ext4 file system.

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.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.