Technical impact
The Linux kernel’s DAMON lru_sort module contains a logic error that triggers a division by zero when users set active_mem_bp above 10,000. In that scenario the cold memory scheme’s target value becomes zero, causing an Oops and kernel panic as shown in the provided reproduction steps. The bug is limited to users with write access to the module parameters, enabling a local attacker with root or equivalent privileges to force a denial of service.
Affected Systems
This defect affects the Linux kernel across all distributions that ship the damon_lru_sort module prior to the fix. Specific vendors are not listed by name, but any system exposing the damon_lru_sort sysfs interface and allowing parameter writes (e.g., wmarks_high, wmarks_mid, wmarks_low, active_mem_bp, enabled) is vulnerable. No version range is provided, so all affected kernel releases containing the unpatched module should be treated as impacted.
Risk and Exploitability
The bug has a *moderate* impact due to an unhandled division leading to a kernel panic. The CVSS score is 5.5, indicating moderate severity. The EPSS score is < 1%, reflecting a very low probability of exploitation, and the flaw is not listed in CISA's KEV catalog. The attack vector is local and requires privileged write permission to the sysfs parameters, which is normally restricted to root. While the exploit is straightforward for an attacker with such access, the lack of remote entry reduces its immediate threat to environments that enforce strict user privileges.
Ubuntu USN