CVE-2026-68165 mm/damon/core: validate ranges in damon_set_regions()
A local attacker can trigger a kernel warning or divide-by-zero crash in DAMON by setting empty monitoring regions, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68165?
CVE-2026-68165 is a denial of service vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: validate ranges in damon_set_regions()
DAMON core logic assumes zero length regions don't exist. However, a few DAMON API callers including DAMON_SYSFS, DAMON_RECLAIM and DAMON_LRU_SORT allow users to set empty monitoring target regions. This could result in WARN_ONCE() on CONFIG_DAMON_DEBUG_SANITY enabled kernel, and divide-by-zero from damon_merge_two_regions().
For example, the WANR_ONCE() can be triggered like below.
# grep DAMON_DEBUG_SANITY /boot/config-$(uname -r) # CONFIG_DAMON_DEBUG_SANITY=y # damo start # cd /sys/kernel/mm/damon/admin/kdamonds/0 # echo 0 > contexts/0/targets/0/regions/0/start # echo 0 > contexts/0/targets/0/regions/0/end # echo commit > state # dmesg [....] [ 73.705780] ------------[ cut here ]------------ [ 73.707552] start 0 >= end 0 [ 73.708452] WARNING: mm/damon/core.c:359 at damon_new_region+0x6e/0x80, CPU#1: kdamond.0/758 [...]
All DAMON API callers eventually use damon_set_regions() to setup the regions. Add the validation logic in the function.
Which versions are affected by CVE-2026-68165?
How do I fix CVE-2026-68165?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-68165 being exploited?
There is no known exploitation of CVE-2026-68165 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68165, DEBIAN-CVE-2026-68165, GHSA-cpwj-jg54-5hr3, UBUNTU-CVE-2026-68165.