CVE-2026-43117: btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file()
In the Linux kernel, the following vulnerability has been resolved:
btrfs: tracepoints: get correct superblock from dentry in event btrfssyncfile()
If overlay is used on top of btrfs, dentry->dsb translates to overlay's super block and fsid assignment will lead to a crash.
Use fileinode(file)->isb to always get btrfssb.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.262-1Fixed in 6.1.176-1Fixed in 6.1.180-1Fixed in 6.12.94-1Fixed in 6.12.101-1Fixed in 7.1.7-1Fixed in 7.1.8-1 - Upgrade
Upgrade
debian/linux-6.1to a version that resolves this vulnerability.Fixed in 6.1.180-1~deb11u1 - Compensating control
If overlay is used on top of btrfs, prevent the problematic tracepoint path (btrfs_sync_file() super block/fsid assignment) until the kernel fix is applied (e.g., avoid using that overlay-on-btrfs configuration in affected kernels).
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43117?
CVE-2026-43117 has been assigned a medium severity rating due to the potential impact on data integrity when using Btrfs with overlays.
How do I fix CVE-2026-43117?
To fix CVE-2026-43117, you should update your Linux kernel to the latest available version that addresses this vulnerability.
What systems are affected by CVE-2026-43117?
CVE-2026-43117 affects Linux kernel versions between 4.8 and 6.6.136, as well as select 7.0 release candidates.
What is the impact of CVE-2026-43117?
The vulnerability can allow incorrect superblock retrieval in Btrfs, potentially leading to data inconsistency.
Is CVE-2026-43117 actively being exploited?
As of now, there are no public reports indicating active exploitation of CVE-2026-43117.