Improper Update of Reference Count Affecting kernel-rt-debug-kvm package, versions <0:5.14.0-503.11.1.el9_5


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-RHEL9-KERNELRTDEBUGKVM-7481372
  • published17 Jul 2024
  • disclosed12 Jul 2024

Introduced: 12 Jul 2024

CVE-2024-40913  (opens in a new tab)
CWE-911  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade RHEL:9 kernel-rt-debug-kvm to version 0:5.14.0-503.11.1.el9_5 or higher.
This issue was patched in RHSA-2024:9315.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-kvm package and not the kernel-rt-debug-kvm package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

cachefiles: defer exposing anon_fd until after copy_to_user() succeeds

After installing the anonymous fd, we can now see it in userland and close it. However, at this point we may not have gotten the reference count of the cache, but we will put it during colse fd, so this may cause a cache UAF.

So grab the cache reference count before fd_install(). In addition, by kernel convention, fd is taken over by the user land after fd_install(), and the kernel should not call close_fd() after that, i.e., it should call fd_install() after everything is ready, thus fd_install() is called after copy_to_user() succeeds.

CVSS Scores

version 3.1