CVE-2026-98242 dma-buf: Fix silent overflow for phys vec to sgt
A silent integer overflow in the Linux kernel's dma-buf subsystem can cause memory corruption or denial of service when handling large MMIO sizes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98242?
CVE-2026-98242 is a vulnerability in Linux, published on 6 Oct 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:
dma-buf: Fix silent overflow for phys vec to sgt
In case MMIO size is bigger than 4G and peer2peer DMA goes through host bridge, we trigger a code path that assigns the total linked IOVA (which is greater than 4G) to mapped_len.
Previously, `mapped_len` was declared as 32-bit `unsigned int`. When accumulating `size_t` lengths, this leads to a silent wrap-around. This truncation causes truncated lengths to be passed to functions like `fill_sg_entry()`.
Fix this by changing `mapped_len` to `size_t` (64-bit). While at it, fix similar potential overflow issues in `calc_sg_nents` by using `check_add_overflow()` for `nents` and using `unsigned int` for the loop iterator in `fill_sg_entry` to match.
Which versions are affected by CVE-2026-98242?
How do I fix CVE-2026-98242?
Apply the vendor's patch.
Is CVE-2026-98242 being exploited?
There is no known exploitation of CVE-2026-98242 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-98242, GHSA-vfw6-gcwv-53h6, UBUNTU-CVE-2026-98242.