CVE-2026-93198 dm-pcache: validate the persisted dirty_tail chain at load
A crafted disk image can cause an infinite loop in the Linux kernel dm-pcache writeback worker, 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-2026-93198?
CVE-2026-93198 is a denial of service vulnerability in Linux, published on 17 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:
dm-pcache: validate the persisted dirty_tail chain at load
The writeback worker follows the persisted dirty_tail chain, which is decoded from the cache device independently of the key_tail chain that cache_replay() walks and bounds. A crafted image, whose on-media fields are authenticated only by a crc32c with a fixed seed, can aim dirty_tail at a chain of last ksets that never terminates, so cache_writeback_fn() re-arms itself with no delay forever.
Walk the dirty_tail chain once at load with the same hop cap cache_replay() uses and fail the table load with -EIO if it does not reach an end within n_segs hops.
Which versions are affected by CVE-2026-93198?
How do I fix CVE-2026-93198?
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-2026-93198 being exploited?
There is no known exploitation of CVE-2026-93198 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-93198, DEBIAN-CVE-2026-93198, GHSA-m9qc-pw52-gvjm, UBUNTU-CVE-2026-93198.