CVE-2026-64124 net: devmem: reject dma-buf bind with non-page-aligned size or SG length
A missing validation in the Linux kernel's devmem driver allows out-of-bounds reads and memory desynchronization via non-page-aligned DMA buffers, potentially leading to crashes or code execution.
- 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-2026-64124?
CVE-2026-64124 is a high-severity memory corruption vulnerability in Linux kernel, published on 19 Jul 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:
net: devmem: reject dma-buf bind with non-page-aligned size or SG length
net_devmem_bind_dmabuf() trusts dmabuf->size and sg_dma_len() to be PAGE_SIZE multiples without checking:
- tx_vec is sized dmabuf->size / PAGE_SIZE, and net_devmem_get_niov_at() only bounds-checks virt_addr < dmabuf->size before indexing tx_vec[virt_addr / PAGE_SIZE]. With size = N*PAGE_SIZE + r (1 <= r < PAGE_SIZE), sendmsg() at iov_base = N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past.
- owner->area.num_niovs = len / PAGE_SIZE while gen_pool_add_owner() covers the full byte len, so a non-page-multiple non-final sg desyncs num_niovs from the gen_pool region for every later sg, on both RX and TX.
dma-buf does not require page-aligned sizes, so the bind path has to enforce what its own indexing assumes. Reject both with -EINVAL.
The size check is TX-only (only tx_vec is sized off dmabuf->size); the SG-length check covers both directions.
Which versions are affected by CVE-2026-64124?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64124?
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-2026-64124 being exploited?
There is no known exploitation of CVE-2026-64124 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-64124, DEBIAN-CVE-2026-64124, GHSA-36q3-p7rr-w76h, UBUNTU-CVE-2026-64124.