CVE-2026-64263
Received
Received - Intake
Heap-based Buffer Overflow in Linux Kernel FUSE-URING
Vulnerability report for CVE-2026-64263, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-07-25
Last updated on: 2026-07-25
Assigner: kernel.org
Description
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
