CVE-2024-35887 Affecting kernel-debug package, versions *

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

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

ax25: fix use-after-free bugs caused by ax25_ds_del_timer

When the ax25 device is detaching, the ax25_dev_device_down() calls ax25_ds_del_timer() to cleanup the slave_timer. When the timer handler is running, the ax25_ds_del_timer() that calls del_timer() in it will return directly. As a result, the use-after-free bugs could happen, one of the scenarios is shown below:

  (Thread 1)          |      (Thread 2)
                      | ax25_ds_timeout()

ax25_dev_device_down() | ax25_ds_del_timer() | del_timer() | ax25_dev_put() //FREE | | ax25_dev-> //USE

In order to mitigate bugs, when the device is detaching, use timer_shutdown_sync() to stop the timer.

• https://access.redhat.com/security/cve/CVE-2024-35887
• https://git.kernel.org/stable/c/74204bf9050f7627aead9875fe4e07ba125cb19b
• https://git.kernel.org/stable/c/c6a368f9c7af4c14b14d390c2543af8001c9bdb9
• https://git.kernel.org/stable/c/fd819ad3ecf6f3c232a06b27423ce9ed8c20da89