Time-of-check Time-of-use (TOCTOU) Affecting kernel package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.12% (3rd percentile)

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  • Snyk IDSNYK-CENTOS10-KERNEL-18036792
  • published21 Jul 2026
  • disclosed19 Jul 2026

Introduced: 19 Jul 2026

NewCVE-2026-64057  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1