# CVE-2023-52474: IB/hfi1: Fix bugs with non-PAGE_SIZE-end multi-iovec user SDMA requests

> A bug in the Linux kernel hfi1 driver allows data corruption and potential information disclosure during user SDMA requests with multiple iovecs.

- **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:** 26 Feb 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-52474, DEBIAN-CVE-2023-52474, GHSA-7r53-r6j6-q893, UBUNTU-CVE-2023-52474

## What is CVE-2023-52474?

CVE-2023-52474 is a high-severity memory corruption vulnerability in Linux kernel, published on 26 Feb 2024. 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:

IB/hfi1: Fix bugs with non-PAGE_SIZE-end multi-iovec user SDMA requests

hfi1 user SDMA request processing has two bugs that can cause data
corruption for user SDMA requests that have multiple payload iovecs
where an iovec other than the tail iovec does not run up to the page
boundary for the buffer pointed to by that iovec.a

Here are the specific bugs:
1. user_sdma_txadd() does not use struct user_sdma_iovec->iov.iov_len.
   Rather, user_sdma_txadd() will add up to PAGE_SIZE bytes from iovec
   to the packet, even if some of those bytes are past
   iovec->iov.iov_len and are thus not intended to be in the packet.
2. user_sdma_txadd() and user_sdma_send_pkts() fail to advance to the
   next iovec in user_sdma_request->iovs when the current iovec
   is not PAGE_SIZE and does not contain enough data to complete the
   packet. The transmitted packet will contain the wrong data from the
   iovec pages.

This has not been an issue with SDMA packets from hfi1 Verbs or PSM2
because they only produce iovecs that end short of PAGE_SIZE as the tail
iovec of an SDMA request.

Fixing these bugs exposes other bugs with the SDMA pin cache
(struct mmu_rb_handler) that get in way of supporting user SDMA requests
with multiple payload iovecs whose buffers do not end at PAGE_SIZE. So
this commit fixes those issues as well.

Here are the mmu_rb_handler bugs that non-PAGE_SIZE-end multi-iovec
payload user SDMA requests can hit:
1. Overlapping memory ranges in mmu_rb_handler will result in duplicate
   pinnings.
2. When extending an existing mmu_rb_handler entry (struct mmu_rb_node),
   the mmu_rb code (1) removes the existing entry under a lock, (2)
   releases that lock, pins the new pages, (3) then reacquires the lock
   to insert the extended mmu_rb_node.

   If someone else comes in and inserts an overlapping entry between (2)
   and (3), insert in (3) will fail.

   The failure path code in this case unpins _all_ pages in either the
   original mmu_rb_node or the new mmu_rb_node that was inserted between
   (2) and (3).
3. In hfi1_mmu_rb_remove_unless_exact(), mmu_rb_node->refcount is
   incremented outside of mmu_rb_handler->lock. As a result, mmu_rb_node
   could be evicted by another thread that gets mmu_rb_handler->lock and
   checks mmu_rb_node->refcount before mmu_rb_node->refcount is
   incremented.
4. Related to #2 above, SDMA request submission failure path does not
   check mmu_rb_node->refcount before freeing mmu_rb_node object.

   If there are other SDMA requests in progress whose iovecs have
   pointers to the now-freed mmu_rb_node(s), those pointers to the
   now-freed mmu_rb nodes will be dereferenced when those SDMA requests
   complete.

## Which versions are affected by CVE-2023-52474?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52474?

Apply the vendor's patch.

## Is CVE-2023-52474 being exploited?

There is no known exploitation of CVE-2023-52474 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-52474 and fix it if it is affected.

What it is: CVE-2023-52474 is a high-severity memory corruption vulnerability in Linux kernel, published on 26 Feb 2024. 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-2023-52474 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2023-52474/ (Markdown: https://insights.sbomify.com/CVE-2023-52474/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52474
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52474
- OSV: https://osv.dev/vulnerability/CVE-2023-52474

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52474/
Summaries are generated and may contain mistakes; the official description above is the record.