CVE-2026-68442

A flaw was found in the btrfs filesystem component of the Linux kernel. When an extent map is split, a flag (EXTENT_FLAG_LOGGING) is incorrectly propagated to the new split maps. This issue occurs because the flag clearing operation was applied to the wrong variable during the splitting process. Consequently, if a split extent map with this flag is freed while still in use, it can lead to a use-after-free vulnerability, potentially causing system instability or a denial of service.

This vulnerability is rated Moderate because exploitation requires local access to write to an active Btrfs filesystem and relies on specific race conditions during extent map logging and memory reclaim. Red Hat Enterprise Linux 8 and 9 are not affected as the vulnerable code introduced in upstream kernel version 6.8 is not present in those releases. On affected environments where Btrfs is mounted, a local user could trigger a kernel use-after-free, leading to a system crash or denial of service.

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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.