CVE-2026-74365 nvdimm/btt: Handle preemption in BTT lane acquisition
A race condition in Linux kernel NVDIMM BTT lane acquisition allows concurrent access, leading to silent data corruption during I/O operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74365?
CVE-2026-74365 is a high-severity vulnerability in Linux, published on 15 Aug 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:
nvdimm/btt: Handle preemption in BTT lane acquisition
BTT lanes serialize access to per-lane metadata and workspace state during BTT I/O. The btt-check unit test reports data mismatches during BTT writes due to a race in lane acquisition that can lead to silent data corruption.
The existing lane model uses a spinlock together with a per-CPU recursion count. That recursion model stopped being valid after BTT lanes became preemptible: another task can run on the same CPU, observe a non-zero recursion count, bypass locking, and use the same lane concurrently.
BTT lanes are also held across arena_write_bytes() calls. That path reaches nsio_rw_bytes(), which flushes writes with nvdimm_flush(). Some provider flush callbacks can sleep, making a spinlock the wrong primitive for the lane lifetime.
Replace the spinlock-based recursion model with a dynamically allocated per-lane mutex array and take the lane lock unconditionally.
Add might_sleep() to catch any future atomic-context caller.
Found with the ndctl unit test btt-check.sh.
Which versions are affected by CVE-2026-74365?
How do I fix CVE-2026-74365?
Apply the vendor's patch.
Is CVE-2026-74365 being exploited?
There is no known exploitation of CVE-2026-74365 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74365, DEBIAN-CVE-2026-74365, GHSA-h26r-wqjv-57jf, UBUNTU-CVE-2026-74365.