CVE-2026-72213 mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch
A logic error in Linux kernel hugetlb cgroup accounting causes counter underflow, potentially leading to system instability or 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-2026-72213?
CVE-2026-72213 is a high-severity 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:
mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch
In alloc_hugetlb_folio(), a single h_cg pointer is used for both the rsvd and non-rsvd hugetlb cgroup charges. When map_chg is set, hugetlb_cgroup_charge_cgroup_rsvd() stores the charged cgroup in h_cg, but the immediately following hugetlb_cgroup_charge_cgroup() overwrites h_cg with the non-rsvd cgroup pointer.
As a result, hugetlb_cgroup_commit_charge_rsvd() stores the wrong (non-rsvd) cgroup pointer into the folio's rsvd slot.
When the folio is later freed, free_huge_folio() unconditionally calls both hugetlb_cgroup_uncharge_folio() and hugetlb_cgroup_uncharge_folio_rsvd(). The rsvd uncharge reads back the wrong cgroup from the folio and decrements a counter that was never charged for that cgroup, causing a page_counter underflow:
page_counter underflow: -512 nr_pages=512 WARNING: mm/page_counter.c:61 at page_counter_cancel
Fix this by introducing a separate h_cg_rsvd pointer exclusively for the rsvd charge path, keeping the rsvd and non-rsvd charges fully independent through their charge, commit, and error uncharge paths.
Which versions are affected by CVE-2026-72213?
How do I fix CVE-2026-72213?
Apply the vendor's patch.
Is CVE-2026-72213 being exploited?
There is no known exploitation of CVE-2026-72213 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72213, DEBIAN-CVE-2026-72213, GHSA-cqhp-gwhx-vmwp, UBUNTU-CVE-2026-72213.