CVE-2026-64067 netfs: Fix missing barriers when accessing stream->subrequests locklessly

What is CVE-2026-64067?

CVE-2026-64067 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 missing barriers when accessing stream->subrequests locklessly

The list of subrequests attached to stream->subrequests is accessed without locks by netfs_collect_read_results() and netfs_collect_write_results(), and then they access subreq->flags without taking a barrier after getting the subreq pointer from the list. Relatedly, the functions that build the list don't use any sort of write barrier when constructing the list to make sure that the NETFS_SREQ_IN_PROGRESS flag is perceived to be set first if no lock is taken.

Fix this by:

(1) Add a new list_add_tail_release() function that uses a release barrier to set the pointer to the new member of the list.

(2) Add a new list_first_entry_or_null_acquire() function that uses an acquire barrier to read the pointer to the first member in a list (or return NULL).

(3) Use list_add_tail_release() when adding a subreq to ->subrequests.

(4) Use list_first_entry_or_null_acquire() when initially accessing the front of the list (when an item is removed, the pointer to the new front iterm is obtained under the same lock).

Weakness: CWE-667

Which versions are affected by CVE-2026-64067?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64067?

Apply the vendor's patch.

Is CVE-2026-64067 being exploited?

There is no known exploitation of CVE-2026-64067 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64067, DEBIAN-CVE-2026-64067, GHSA-f3mp-m5hm-h688, ROOT-OS-DEBIAN-13-CVE-2026-64067, UBUNTU-CVE-2026-64067.