CVE-2026-64069: netfs: Fix cancellation of a DIO and single read subrequests
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 netfsqueueread() to do the queuing.
(3) Set NETFSRREQALLQUEUED 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 NETFSSREQFAILED flag on the subreq and then call netfsreadsubreqterminated() to deal with it. This will pass responsibility off to the collector for dealing with it.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
Harmonise buffered, DIO, and single-read paths so all three call netfs_queue_read() to queue the subrequest.
- Compensating control
Set NETFS_RREQ_ALL_QUEUED independently of queuing, and in every failure case set the error and NETFS_SREQ_FAILED flag on the subrequest.
- Compensating control
Fix cancellation of failed DIO-read and single-read subrequests: if preparation fails before the subrequest is queued, put and abandon it; if it has already been added to stream->subrequests, leave responsibility to the collector and call netfs_read_subreq_terminated().
Event History
Frequently Asked Questions
What is the severity of CVE-2026-64069?
CVE-2026-64069 has a critical severity rating of 9.8 according to CVSS 3.1.
What does CVE-2026-64069 affect?
CVE-2026-64069 affects the Linux kernel, specifically the netfs component.
How do I fix CVE-2026-64069?
To fix CVE-2026-64069, upgrade to the latest patched version of the Linux kernel that addresses this vulnerability.
What type of vulnerability is CVE-2026-64069?
CVE-2026-64069 is a vulnerability that involves the cancellation of a Direct I/O and single read subrequests in the Linux kernel.
Was there a workaround for CVE-2026-64069 before it was patched?
No official workaround was provided for CVE-2026-64069, making it essential to apply the patch.