# CVE-2026-74390: RDMA/irdma: Fix out-of-bounds write in irdma_copy_user_pgaddrs

> A local attacker can trigger an out-of-bounds write in the Linux kernel's irdma driver, potentially leading to code execution or 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:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-74390, DEBIAN-CVE-2026-74390, GHSA-c23v-2w7h-h6m9, UBUNTU-CVE-2026-74390

## What is CVE-2026-74390?

CVE-2026-74390 is a high-severity 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 out-of-bounds write in irdma_copy_user_pgaddrs

The irdma_copy_user_pgaddrs function loops through all of the umem DMA
blocks to populate the PBLEs and will stop when either the last DMA
block is reached or palloc->total_cnt is reached. The issue is that
the logic for checking palloc->total_cnt would only work for non-zero
values.

When irdma_setup_pbles is called with lvl==0, it
calls irdma_copy_user_pgaddrs with palloc->total_cnt==0, which means
the only way to break out of the loop is to reach the last umem DMA
block, which means it could end up going beyond the fixed size of 4
iwmr->pgaddrmem array that is used in the lvl==0 case.

In the case of QP/CQ/SRQ rings, the value of lvl is determined by a
separate input (for example, req.cq_pages in the case of a CQ). So,
we must perform explicit checking to ensure we don't overflow the
pgaddrmem array if the user provides a umem that consists of more
blocks than their provided req.cq_pages.

## Which versions are affected by CVE-2026-74390?


## How do I fix CVE-2026-74390?

Apply the vendor's patch.

## Is CVE-2026-74390 being exploited?

There is no known exploitation of CVE-2026-74390 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74390 and fix it if it is affected.

What it is: CVE-2026-74390 is a high-severity 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-2026-74390 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-2026-74390/ (Markdown: https://insights.sbomify.com/CVE-2026-74390/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74390
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74390
- OSV: https://osv.dev/vulnerability/CVE-2026-74390

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74390/
Summaries are generated and may contain mistakes; the official description above is the record.