CVE-2026-64057 afs: Fix the locking used by afs_get_link()

What is CVE-2026-64057?

CVE-2026-64057 is a high-severity vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

afs: Fix the locking used by afs_get_link()

The afs filesystem in the kernel doesn't do locking correctly for symbolic links. There are a number of problems:

(1) It doesn't do any locking around afs_read_single() to prevent races between multiple ->get_link() calls, thereby allowing the possibility of leaks.

(2) It doesn't use RCU barriering when accessing the buffer pointers during RCU pathwalk.

(3) It can race with another thread updating the contents of the symlink if a third party updated it on the server.

Fix this by the following means:

(0) Move symlink handling into its own file as this makes it more complicated.

(1) Take the validate_lock around afs_read_single() to prevent races between multiple ->get_link() calls.

(2) Keep a separate copy of the symlink contents with an rcu_head. This is always going to be a lot smaller than a page, so it can be kmalloc'd and save quite a bit of memory. It also needs a refcount for non-RCU pathwalk.

(3) Split the symlink read and write-to-cache routines in afs from those for directories.

(4) Discard the I/O buffer as soon as the write-to-cache completes as this is a full page (plus a folio_queue).

(5) If there's no cache, discard the I/O buffer immediately after reading and copying if there is no cache.

Weakness: CWE-667

Which versions are affected by CVE-2026-64057?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64057?

Apply the vendor's patch.

Is CVE-2026-64057 being exploited?

There is no known exploitation of CVE-2026-64057 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-2026-64057, DEBIAN-CVE-2026-64057, GHSA-8264-g9fh-vx2h, UBUNTU-CVE-2026-64057.