CVE-2026-98446 xfs: don't let hidden_space go negative in xfs_metafile_resv_init
An integer underflow in the Linux kernel XFS filesystem can cause excessive space reservation, leading to a 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-2026-98446?
CVE-2026-98446 is a vulnerability in Linux, published on 18 Oct 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:
xfs: don't let hidden_space go negative in xfs_metafile_resv_init
LOLLM points out that if the amount of fdblocks that we can reserve for a metadata btree file goes below the space already used by that file, then the hidden_space subtraction can underflow, causing xfs_dec_fdblocks to subtract a huge amount of space. We never want the target to be less than the used sapce, so fix the logic that adjusts dblocks_avail downwards.
Also fix an error in the adjacent comment.
Which versions are affected by CVE-2026-98446?
How do I fix CVE-2026-98446?
Apply the vendor's patch.
Is CVE-2026-98446 being exploited?
There is no known exploitation of CVE-2026-98446 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-98446, DEBIAN-CVE-2026-98446, GHSA-8r8r-jgjj-w55r, UBUNTU-CVE-2026-98446.