CVE-2026-64069
Received Received - Intake

netfs: Fix Subrequest Cancellation in Linux Kernel

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

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.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-64069
EUVD
EUVD-2026-45642

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves incorrect handling of read subrequests when preparation fails. It affects the netfs subsystem, specifically when a new subrequest for reading data fails during setup. The issue arises because the subrequest may already be linked to a list or still hold outstanding references, leading to improper cleanup. The fix ensures consistent handling across buffered, direct I/O (DIO), and single-read operations by standardizing the queuing process before preparation and properly marking failed subrequests for termination.

Detection Guidance

This vulnerability is specific to the Linux kernel's netfs subsystem and relates to subrequest handling during read operations. Detection requires checking kernel logs for errors related to netfs, subrequest failures, or read operations. Commands like dmesg, journalctl -k, or checking kernel ring buffer logs may help identify issues. No direct commands are provided in the context to exploit or detect this vulnerability.

Impact Analysis

This vulnerability could lead to system instability or crashes if exploited, as improper handling of failed read subrequests may corrupt kernel memory or cause unexpected behavior. Users relying on affected Linux kernel versions might experience data corruption, application failures, or system hangs during file operations, particularly when using network filesystems or direct I/O operations.

Compliance Impact

This vulnerability affects the Linux kernel's netfs subsystem, specifically related to read operations. It does not directly impact compliance with standards like GDPR or HIPAA as it is a low-level kernel issue affecting file read operations. Compliance implications would depend on how the affected kernel is used in a system handling regulated data.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve this issue. Monitor kernel logs for read subrequest failures as potential indicators of exploitation.

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