CVE-2026-64260: fuse-uring: Avoid queue->stopped races and set/read that value under lock

From: Greg Kroah-Hartman <[email protected]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

fuse-uring: Avoid queue->stopped races and set/read that value under lock

There are several readers of queue->stopped that check the value
under lock, but fuse_uring_commit_fetch() did not and actually
the value was not set under the lock in fuse_uring_abort_end_requests()
either. Especially in fuse_uring_commit_fetch it is important
to check under a lock, because due to races 'struct fuse_req'
might be freed with fuse_request_end, but another thread/cpu
might already do teardown work.

The Linux kernel CVE team has assigned CVE-2026-64260 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.14 with commit 4a9bfb9b6850fec0685447aed280533cf980de70 and fixed in 6.18.39 with commit 39c8e925b207afceffaa5382416ed405e0223a03
	Issue introduced in 6.14 with commit 4a9bfb9b6850fec0685447aed280533cf980de70 and fixed in 7.1.4 with commit 4021a3a79eee551d95fe1e1e7c1b195d34ba8c08
	Issue introduced in 6.14 with commit 4a9bfb9b6850fec0685447aed280533cf980de70 and fixed in 7.2-rc1 with commit b70a3aca16934c196f92abb17b01c1647b9bb63c

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-64260
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/fuse/dev_uring.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/39c8e925b207afceffaa5382416ed405e0223a03
	https://git.kernel.org/stable/c/4021a3a79eee551d95fe1e1e7c1b195d34ba8c08
	https://git.kernel.org/stable/c/b70a3aca16934c196f92abb17b01c1647b9bb63c