CVE-2026-74524 riscv: mm: Fix out-of-bounds page-table walk during memory hot-remove
A memory hot-remove flaw in the RISC-V Linux kernel allows out-of-bounds page-table walks, potentially causing system crashes or arbitrary code execution.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74524?
CVE-2026-74524 is a memory corruption 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:
riscv: mm: Fix out-of-bounds page-table walk during memory hot-remove
remove_pud_mapping() and remove_p4d_mapping() obtain a child table base with pud_offset(p4dp, 0) and p4d_offset(pgd, 0), then add the index for addr.
RISC-V folds page-table levels at runtime. When a level is folded, its offset helper returns the parent entry itself, but the index can still be nonzero. Adding it walks past the parent table. Sv48 folds P4D, while Sv39 folds both P4D and PUD, so memory hot-remove can descend into unrelated memory and pass an invalid page to __free_pages(). This can trigger:
kernel BUG at include/linux/mm.h:1810! VM_BUG_ON_PAGE(page_ref_count(page) == 0) arch_remove_memory+0x1e/0x5c try_remove_memory+0x15e/0x200 remove_memory+0x24/0x3c
Only add the index when the corresponding page-table level is enabled, matching p4d_offset() and pud_offset().
Which versions are affected by CVE-2026-74524?
How do I fix CVE-2026-74524?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-74524 being exploited?
There is no known exploitation of CVE-2026-74524 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74524, DEBIAN-CVE-2026-74524, GHSA-273p-44hj-2v3c, UBUNTU-CVE-2026-74524.