CVE-2025-39738

A flaw was found in the Linux kernel. A local user can trigger a transaction abort and a warning in the Btrfs (B-tree file system) by attempting to relocate a partially dropped subvolume that lacks an orphan item. This vulnerability can lead to a Denial of Service (DoS) by causing the system to become unresponsive or crash.

A denial of service vulnerability was found in the Linux kernel's Btrfs (B-tree file system) implementation. A local user able to trigger block relocation (for example, by running a balance operation) on a Btrfs file system that contains a partially dropped subvolume lacking an orphan item can cause a transaction abort and a kernel warning, leaving the file system unresponsive and potentially crashing the system. In Red Hat Enterprise Linux, this issue affects the kernel and kernel-rt packages in the Red Hat Enterprise Linux 7 Extended Lifecycle Support streams, where the fix has been deferred; the residual risk is limited to a local user triggering this denial of service on affected Btrfs file systems, with no impact on the confidentiality or integrity of data. Red Hat Enterprise Linux 8, 9, and 10, and Red Hat In-Vehicle OS are not affected because the vulnerable code is not present in those releases. Red Hat rates this flaw as Moderate severity (CVSS 5.5, availability impact only), which is lower than the NIST score of 7.8, because this flaw affects only system availability and does not compromise confidentiality or integrity.

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.