Medium [CVE-2026-80622] fix use-after-free in tlclk_cleanup
This medium-severity Red Hat Linux advisory covers CVE-2026-80622 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
In the Linux kernel, the following vulnerability has been resolved: char: tlclk: fix use-after-free in tlclk_cleanup() This patch improves the module cleanup process in the tlclk driver to prevent potential use-after-free and race conditions.
Currently, the file_operations structure does not specify the.owner field, which could allow the module to be unloaded while user-space processes are still interacting with the device.
Additionally, the tlclk_cleanup() function frees the alarm_events memory before ensuring that blocked processes in the waitqueue are fully awakened and that the switchover_timer has completed.
To address these cases, this patch: - Sets '.owner = THIS_MODULE' in tlclk_fops to safely defer module unloading while the device is in use. - Updates tlclk_cleanup() to explicitly wake up all blocked readers (wake_up_all), properly release hardware I/O regions, and safely delete the timer (timer_delete_sync) prior to freeing memory.
This vulnerability occurs due to improper module cleanup, where the driver can be unloaded while user-space processes are still active, and memory is freed prematurely. A local attacker could potentially exploit this to cause a denial of service or achieve privilege escalation.
Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-367.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 57 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 57 minutes ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 57 minutes ago·verify at source
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