CVE Catalog

CVE-2026-64263

MediumCVSS 5.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.15%

5th percentile - higher than 5% of all known CVEs

Summary

In the Linux kernel fuse-uring subsystem, a vulnerability leads to a NULL pointer dereference. The fuse_uring_cancel() function moves cancelled entries to the ent_in_userspace list, and ent_list_request_expired() dereferences ent->fuse_req without checking, causing a crash.

Risk Assessment

An attacker could cause a system crash (DoS) by sending specially crafted io_uring requests.

Recommendation

Apply the Linux kernel patch that frees the entry and decrements queue_refs directly in fuse_uring_cancel().

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix moving cancelled entry to ent_in_userspace list fuse_uring_cancel() moves entries that are available (these have no reqs attached) to the ent_in_userspace list. ent_list_request_expired() checks the first entry on ent_in_userspace and dereferences ent->fuse_req unconditionally, which will crash on a cancelled entry that was moved to this list. Fix this by freeing the entry and dropping queue_refs directly in fuse_uring_cancel(). This is safe because cancel is the cancel handler itself - after io_uring_cmd_done(), no more cancels will be dispatched for this command, and teardown serializes with cancel via queue->lock. Since cancel now decrements queue_refs, fuse_uring_abort() must no longer gate fuse_uring_abort_end_requests() on queue_refs > 0, as cancelled entries may have already dropped queue_refs while requests are still queued. Remove the gate so abort always flushes requests and stops queues.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS