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HIGH

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

Published May 21, 2024

Description

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.

Affected products

Remediation

Red Hat statement

This vulnerability is rated as a moderate severity because this issue does not allow unauthorized access or data leakage, but it poses a risk of system instability and crashes. The potential for a use-after-free condition can disrupt normal operations.

Red Hat mitigation

Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.

Weaknesses (1)

CWE-416

Use After Free

References (14)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner Linux
Published May 21, 2024
Updated May 11, 2026
Reserved May 21, 2024
Link CVE-2021-47321
CISA Vulnrichment
Updated Sep 10, 2024
NVD
Status Analyzed
Modified Jun 17, 2026
Link CVE-2021-47321
Red Hat
Severity Moderate
Public date May 21, 2024
Links CVE-2021-47321 - Bugzilla
ENISA EUVD
Assigner n/a
Published n/a
Updated n/a
Exploited since n/a
Link n/a