CVE-2026-64588: fuse-uring: fix data races on ring->ready

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-06 · updated 2026-08-17

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.

Affected products

Linux kernel: 6.14 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-64588 or the next vulnerability affects your stack