Use After Free Affecting kernel-core package, versions <0:4.18.0-553.22.1.el8_10


Severity

Recommended
high

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (15th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELCORE-6999639
  • published28 May 2024
  • disclosed21 May 2024

Introduced: 21 May 2024

CVE-2021-47321  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade RHEL:8 kernel-core to version 0:4.18.0-553.22.1.el8_10 or higher.
This issue was patched in RHSA-2024:7000.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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

watchdog: Fix possible use-after-free by calling del_timer_sync()

This driver's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.

CVSS Scores

version 3.1