CVE-2026-64069 netfs: Fix cancellation of a DIO and single read subrequests
A flaw in Linux kernel netfs subrequest cancellation can cause a null pointer dereference, leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64069?
CVE-2026-64069 is a critical vulnerability in Linux kernel, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix cancellation of a DIO and single read subrequests
When the preparation of a new subrequest for a read fails, if the subrequest has already been added to the stream->subrequests list, it can't simply be put and abandoned as the collector may see it. Also, if it hasn't been queued yet, it has two outstanding refs that both need to be put. Both DIO read and single-read dispatch fail at this; further, both differ in the order they do things to the way buffered read works.
Fix cancellation of both DIO-read and single-read subrequests that failed preparation by the following steps:
(1) Harmonise all three reads (buffered, dio, single) to queue the subreq before prepping it.
(2) Make all three call netfs_queue_read() to do the queuing.
(3) Set NETFS_RREQ_ALL_QUEUED independently of the queuing as we don't know the length of the subreq at this point.
(4) In all cases, set the error and NETFS_SREQ_FAILED flag on the subreq and then call netfs_read_subreq_terminated() to deal with it. This will pass responsibility off to the collector for dealing with it.
Weakness: CWE-125
Which versions are affected by CVE-2026-64069?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64069?
Apply the vendor's patch.
Is CVE-2026-64069 being exploited?
There is no known exploitation of CVE-2026-64069 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-64069, DEBIAN-CVE-2026-64069, GHSA-95rq-8wg2-8c57, UBUNTU-CVE-2026-64069.