CVE-2026-97416
kernel: btrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()
Severity
LowRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · September 24, 2026
Updated · October 18, 2026
Description
A flaw was found in the Linux kernel's Btrfs file system. An attacker could exploit this vulnerability by mounting a corrupted file system image and initiating a balance operation. Due to a missing validation check when querying block group metadata, the kernel triggers a null pointer dereference and crashes, resulting in a Denial of Service (DoS).
Statement
A low impact NULL pointer dereference flaw was found in the Linux kernel's Btrfs file system implementation. When a corrupted filesystem image contains a chunk item in the chunk tree without a corresponding block group in the in-memory cache, running a Btrfs balance operation causes btrfs_may_alloc_data_chunk() to dereference the NULL pointer returned by btrfs_lookup_block_group(), crashing the kernel and resulting in a local denial of service. There is no impact to confidentiality or integrity. Exploitation requires local access with the privileges needed to mount a crafted Btrfs filesystem image and issue the balance ioctl (for example CAP_SYS_ADMIN), which limits the practical severity, and Red Hat therefore rates the overall impact of this flaw as Low. The currently affected Red Hat products are the Red Hat Enterprise Linux 10 kernel and the Red Hat In-Vehicle OS 2 kernel offerings; for these streams the fix is deferred to a future update, and the residual risk is limited to a local denial of service that requires an already-corrupted filesystem image and privileged administrative action. Red Hat Enterprise Linux 7, 8, and 9 (including the kernel-rt packages) and the OpenShift Container Platform RHEL CoreOS images are not affected because the vulnerable code is not present in those releases, and the Red Hat Enterprise Linux 6 Extended Lifecycle Support kernel is out of support scope for this flaw.
CVSS score applicability
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
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.
CVSS / CWE
CVSS 3.1 · 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-476 · NULL Pointer Dereference