CVE-2023-53778 accel/qaic: Clean up integer overflow checking in map_user_pages()
An integer overflow in the Linux kernel QAIC driver allows attackers to bypass size checks, potentially leading to memory corruption and privilege escalation.
- 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-2023-53778?
CVE-2023-53778 is a high-severity vulnerability in Linux, published on 9 Dec 2025. 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:
accel/qaic: Clean up integer overflow checking in map_user_pages()
The encode_dma() function has some validation on in_trans->size but it would be more clear to move those checks to find_and_map_user_pages().
The encode_dma() had two checks:
if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size) return -EINVAL;
The in_trans->addr variable is the starting address. The in_trans->size variable is the total size of the transfer. The transfer can occur in parts and the resources->xferred_dma_size tracks how many bytes we have already transferred.
This patch introduces a new variable "remaining" which represents the amount we want to transfer (in_trans->size) minus the amount we have already transferred (resources->xferred_dma_size).
I have modified the check for if in_trans->size is zero to instead check if in_trans->size is less than resources->xferred_dma_size. If we have already transferred more bytes than in_trans->size then there are negative bytes remaining which doesn't make sense. If there are zero bytes remaining to be copied, just return success.
The check in encode_dma() checked that "addr + size" could not overflow and barring a driver bug that should work, but it's easier to check if we do this in parts. First check that "in_trans->addr + resources->xferred_dma_size" is safe. Then check that "xfer_start_addr + remaining" is safe.
My final concern was that we are dealing with u64 values but on 32bit systems the kmalloc() function will truncate the sizes to 32 bits. So I calculated "total = in_trans->size + offset_in_page(xfer_start_addr);" and returned -EINVAL if it were >= SIZE_MAX. This will not affect 64bit systems.
Which versions are affected by CVE-2023-53778?
How do I fix CVE-2023-53778?
Apply the vendor's patch.
Is CVE-2023-53778 being exploited?
There is no known exploitation of CVE-2023-53778 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53778, DEBIAN-CVE-2023-53778, GHSA-xj22-vpw4-jv3x, UBUNTU-CVE-2023-53778.