CVE-2026-68172 arm64: make huge_ptep_get handled unaligned addresses
A local attacker can trigger a kernel panic by causing the arm64 huge_ptep_get function to dereference an invalid pointer when handling unaligned addresses.
- 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-2026-68172?
CVE-2026-68172 is a high-severity 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:
arm64: make huge_ptep_get handled unaligned addresses
huge_ptep_get() can be handed a virtual address pointing to the middle of a contpmd/contpte mapped hugetlb folio (examples of callers are pagemap_hugetlb_range, page_mapped_in_vma).
The arm64 helper rewalks the pgtables in find_num_contig to answer whether the huge pte we have maps a contpmd or a contpte hugetlb folio, and returns CONT_PMDS or CONT_PTES, so that it can collect a/d bits over the contiguous ptes. We can falsely return CONT_PTES instead of CONT_PMDS if the addr is not aligned. On systems where CONT_PTES != CONT_PMDS (meaning page size is 16K), we could collect excess A/D bit state, meaning extra work for the kernel. Even worse, we may iterate beyond the PTE table and dereference a garbage ptep pointer to access physical memory we don't own. Since the ptep pointer is a linear map address, we may run off the end of the linear map or into a hole, dereference a VA not mapped into the kernel pgtables and cause kernel panic.
Fix this by aligning the pmdp pointer down to a contpmd base before checking equality with the passed huge pte pointer, to correctly answer whether the huge pte is the base of a contpmd block.
Which versions are affected by CVE-2026-68172?
How do I fix CVE-2026-68172?
Apply the vendor's patch.
Is CVE-2026-68172 being exploited?
There is no known exploitation of CVE-2026-68172 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68172, DEBIAN-CVE-2026-68172, GHSA-mc2f-cm9p-679q, UBUNTU-CVE-2026-68172.