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CVE-2026-97416 json

btrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()

published 2026-09-24 46 d ago modified 2026-10-03 37 d ago also EUVD-2026-86029

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

btrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()

[BUG] Running btrfs balance can trigger a null-ptr-deref before relocating a data chunk when metadata corruption leaves a chunk in the chunk tree without a corresponding block group in the in-memory cache:

KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f] RIP: 0010:btrfs_may_alloc_data_chunk+0x40/0x1c0 fs/btrfs/volumes.c:3601 Call Trace: __btrfs_balance fs/btrfs/volumes.c:4217 [inline] btrfs_balance+0x2516/0x42b0 fs/btrfs/volumes.c:4604 btrfs_ioctl_balance fs/btrfs/ioctl.c:3577 [inline] btrfs_ioctl+0x25cf/0x5b90 fs/btrfs/ioctl.c:5313 ...

[CAUSE] __btrfs_balance() iterates the on-disk chunk tree and passes the chunk logical bytenr to btrfs_may_alloc_data_chunk() before relocating a data chunk. That helper then queries the in-memory block group cache:

cache = btrfs_lookup_block_group(fs_info, chunk_offset); chunk_type = cache->flags; /* cache may be NULL */

A corrupt image can contain a chunk item whose matching block group item is missing, so no block group is ever inserted into the cache. In that case btrfs_lookup_block_group() returns NULL.

The code only guards this with ASSERT(cache), which becomes a no-op when CONFIG_BTRFS_ASSERT is disabled. The subsequent dereference of cache->flags therefore crashes the kernel.

[FIX] Add a NULL check after btrfs_lookup_block_group() in btrfs_may_alloc_data_chunk() and print and error message for clarity.

Patch / fix

  • Linux Linux 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-97416

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-97416

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt Real Time Module 15 SP7 6.4.0-150700.7.81.1
  • kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.81.1
  • kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.81.1
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.87.3
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.87.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.87.3
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.87.3
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.87.3

suse advisories SUSE-SU-2026:4940-1SUSE-SU-2026:4935-1SUSE-SU-2026:24473-1SUSE-SU-2026:24553-1SUSE-SU-2026:24422-1SUSE-SU-2026:24446-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.40.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.40.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.40.1

opensuse advisories openSUSE-SU-2026:22167-1

  • kernel Azure Linux 3.0 6.6.158.1-1

azure linux advisories AZL-103586

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-97416 updated cvss 5.5

kernel: btrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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