# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 9 Dec 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-53778, DEBIAN-CVE-2023-53778, GHSA-xj22-vpw4-jv3x, UBUNTU-CVE-2023-53778

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-53778 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2023-53778 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-53778/ (Markdown: https://insights.sbomify.com/CVE-2023-53778/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53778
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53778
- OSV: https://osv.dev/vulnerability/CVE-2023-53778

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53778/
Summaries are generated and may contain mistakes; the official description above is the record.