CVE-2026-72010 cgroup/cpuset: rebind mm mempolicy to effective_mems, not mems_allowed
A local attacker can cause a kernel crash via division by zero in cpuset memory policy rebinding during CPU hotplug events.
- 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-2026-72010?
CVE-2026-72010 is a denial of service vulnerability in Linux, published on 15 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:
cgroup/cpuset: rebind mm mempolicy to effective_mems, not mems_allowed
Creating a child cpuset where cpuset.mems is never set leads to a div/0 when a VMA mempolicy with MPOL_F_RELATIVE_NODES rebinds in response to a CPU hotplug event.
Reproduction steps: 1) Create a cgroup w/ cpuset controls (do not set cpuset.mems) 2) Move the task into the child cpuset 3) Create a VMA mempolicy for that task with MPOL_F_RELATIVE_NODES 4) unplug and hotplug a cpu echo 0 > /sys/devices/system/cpu/cpu1/online echo 1 > /sys/devices/system/cpu/cpu1/online 5) mempolicy rebind does a div/0 in mpol_relative_nodemask on the call to __nodes_fold()
The cpuset code passes (cs->mems_allowed) which is not guaranteed to have nodes to the rebind routine. Use cs->effective_mems instead, which is guaranteed to have a non-empty nodemask once we reach that code path.
[ david: add a comment, slightly rephrase description ]
Which versions are affected by CVE-2026-72010?
How do I fix CVE-2026-72010?
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-2026-72010 being exploited?
There is no known exploitation of CVE-2026-72010 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72010, DEBIAN-CVE-2026-72010, GHSA-m46q-74wj-vxmp, UBUNTU-CVE-2026-72010.