CVE-2026-64588 fuse-uring: fix data races on ring->ready
A data race in the Linux kernel's fuse-uring module allows stale pointer usage, potentially leading to code execution or privilege escalation.
- 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-2026-64588?
CVE-2026-64588 is a high-severity vulnerability in Linux, published on 6 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:
fuse-uring: fix data races on ring->ready
On weakly-ordered architectures, the store to fiq->ops can be reordered past the store to ring->ready, allowing a CPU that sees ring->ready == true via fuse_uring_ready() to dispatch requests through a stale fiq->ops pointer. Upgrade the store to smp_store_release() and the load in fuse_uring_ready() to smp_load_acquire() so that the preceding WRITE_ONCE(fiq->ops, ...) is visible to any CPU that observes ring->ready == true.
Additionally, fuse_uring_do_register() publishes ring->ready with WRITE_ONCE() but the fast-path check reads it with a plain load. This is a marked-vs-unmarked access that KCSAN will flag. Wrap it in READ_ONCE() to mark it without adding unnecessary ordering.
Also wrap the fc->ring load in fuse_uring_ready() in READ_ONCE() to prevent the compiler from reloading it between the NULL check and the dereference.
Which versions are affected by CVE-2026-64588?
How do I fix CVE-2026-64588?
Apply the vendor's patch.
Is CVE-2026-64588 being exploited?
There is no known exploitation of CVE-2026-64588 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-64588, DEBIAN-CVE-2026-64588, GHSA-ww4g-j47r-8q39, UBUNTU-CVE-2026-64588.