The Linux kernel contained a vulnerability where callbacks in enabled_monitors_seq_ops treated the iterator inconsistently—some as struct rv_monitor * and others as struct list_head *. This caused incorrect type casting leading to system crashes. The fix involved converting all usage to struct list_head * as the iterator, aligning enabled_monitors with available_monitors for consistency. This vulnerability affects numerous specific kernel versions across linux-hwe-edge and related Ubuntu kernel packages. Ubuntu's security advisories USN-7920-1 and USN-7920-2 detail the fixes, which also address other kernel security issues in tracing infrastructure and Netfilter subsystems. The updates require rebooting and recompiling third-party kernel modules due to ABI changes. There are no known active exploits for this vulnerability.

The vulnerability causes system crashes due to wrong type casting in kernel iterator usage, potentially leading to denial of service. There is no evidence of privilege escalation or remote code execution. No known exploits are reported in the wild. The impact is limited to system stability and reliability.

A patch is available and should be applied by updating to the fixed kernel package versions provided by Ubuntu in advisories USN-7920-1 and USN-7920-2. After updating, a system reboot is required to activate the fixes. Due to an ABI change, all third-party kernel modules must be recompiled and reinstalled. Users should follow standard Ubuntu update procedures to ensure the system is protected.