# CVE-2026-74346: RDMA/irdma: Fix OOB read during CQ MR registration

> An out-of-bounds read in the Linux kernel's irdma driver allows attackers to read kernel memory or cause a crash during CQ memory registration.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-74346, DEBIAN-CVE-2026-74346, GHSA-r8xx-cvrr-fwj4, UBUNTU-CVE-2026-74346

## What is CVE-2026-74346?

CVE-2026-74346 is a memory corruption vulnerability in Linux, published on 15 Aug 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:

RDMA/irdma: Fix OOB read during CQ MR registration

Sashiko pointed out an unrelated bug during a previous patch:
https://sashiko.dev/#/patchset/20260512183852.614045-1-jmoroni%40google.com

This change fixes the bug by eliminating the cqmr->split field which
was not being set properly and instead just checks the CQ resize
feature flag directly.

The cqmr->split field essentially tracks whether IRDMA_FEATURE_CQ_RESIZE
is set, but it was not being set until CQ creation time, which is _after_
CQ memory registration (the only other place where it is referenced).

As a result, it would always be false during MR registration and would
therefore cause irdma_handle_q_mem to populate cqmr->shadow even for GEN_2
HW and beyond:

    cqmr->shadow = (dma_addr_t)arr[req->cq_pages];

The issue is that for GEN_2 and beyond, req->cq_pages may be exactly equal
to iwmr->page_cnt and therefore equal to the size of arr, which would cause
an OOB read by one.

## Which versions are affected by CVE-2026-74346?


## How do I fix CVE-2026-74346?

Apply the vendor's patch.

## Is CVE-2026-74346 being exploited?

There is no known exploitation of CVE-2026-74346 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74346 and fix it if it is affected.

What it is: CVE-2026-74346 is a memory corruption vulnerability in Linux, published on 15 Aug 2026. 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-2026-74346 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-2026-74346/ (Markdown: https://insights.sbomify.com/CVE-2026-74346/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74346
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74346
- OSV: https://osv.dev/vulnerability/CVE-2026-74346

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74346/
Summaries are generated and may contain mistakes; the official description above is the record.