CVE-2026-97534 f2fs: accurately adjust free_sections during free_segment_range
A logic error in the Linux kernel's f2fs filesystem can cause allocation failures and assertion errors, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97534?
CVE-2026-97534 is a denial of service vulnerability in Linux, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
f2fs: accurately adjust free_sections during free_segment_range
In free_segment_range(), MAIN_SECS(sbi) is temporarily reduced by `secs` to restrict block allocation to the safe remaining main area while valid blocks in the truncated range are evacuated by GC.
However, FREE_I(sbi)->free_sections tracks the total number of free sections across the whole filesystem. If any sections within the truncated range were already free upon entering free_segment_range(), failing to deduct them from free_sections causes the filesystem to overestimate available free sections in the active, reduced main area. This leads to inconsistent free section accounting during GC data migration and can trigger unexpected allocation failures or assertion errors when space is tight.
Fix this by calculating the number of already-free sections in the truncated range, deducting them from free_sections upon entering free_segment_range(), and restoring them on exit.
Which versions are affected by CVE-2026-97534?
How do I fix CVE-2026-97534?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-97534 being exploited?
There is no known exploitation of CVE-2026-97534 in the wild and no public exploit code.
Sources
Also known as AZL-104532, BELL-CVE-2026-97534, DEBIAN-CVE-2026-97534, GHSA-9m8h-hg7g-4xp7, UBUNTU-CVE-2026-97534.