# CVE-2026-97421: RDMA/umem: Be careful about boundary conditions in ib_umem_find_best_pgsz()

> Integer overflow in Linux kernel RDMA memory handling can cause boundary condition errors, potentially leading to system instability or crashes.

- **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:** 24 Sep 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-103682, BELL-CVE-2026-97421, DEBIAN-CVE-2026-97421, GHSA-rfxq-r256-5mj8, UBUNTU-CVE-2026-97421

## What is CVE-2026-97421?

CVE-2026-97421 is a high-severity vulnerability in Linux, published on 24 Sep 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/umem: Be careful about boundary conditions in ib_umem_find_best_pgsz()

Several corner cases, especially important on 32 bits:

- umem->iova is u64, the function argument should pass in u64 or
  iova will be truncated
- Check that the length is not too large for the iova
- Check that lengths > 4G don't overflow the GENMASK

## Which versions are affected by CVE-2026-97421?


## How do I fix CVE-2026-97421?

Apply the vendor's patch.

## Is CVE-2026-97421 being exploited?

There is no known exploitation of CVE-2026-97421 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97421 and fix it if it is affected.

What it is: CVE-2026-97421 is a high-severity vulnerability in Linux, published on 24 Sep 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-2026-97421 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-2026-97421/ (Markdown: https://insights.sbomify.com/CVE-2026-97421/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97421
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97421
- OSV: https://osv.dev/vulnerability/CVE-2026-97421

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97421/
Summaries are generated and may contain mistakes; the official description above is the record.