# CVE-2026-68419: RDMA/irdma: Prevent rereg_mr for non-mem regions

> A local attacker can trigger a denial of service in the Linux kernel by invoking rereg_mr on special RDMA memory regions with invalid keys.

- **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:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68419, DEBIAN-CVE-2026-68419, GHSA-f527-f42m-rc5q, UBUNTU-CVE-2026-68419

## What is CVE-2026-68419?

CVE-2026-68419 is a high-severity vulnerability in Linux, published on 10 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: Prevent rereg_mr for non-mem regions

When a QP/CQ/SRQ is created, a two step process is used
where the buffer is allocated in userspace and explicitly
registered with the normal reg_mr mechanism prior to creating
the actual QP/CQ/SRQ object.

These special registrations are indicated via an ABI field
so the driver knows that they do not have a valid mkey and
to skip the actual CQP command submission.

Since these are real MR objects from the core's perspective,
it is possible for a user application to invoke rereg_mr on them
and cause a real CQP op to be emitted with the zero-initialized
mkey value of 0.

Fix this by preventing rereg_mr on these special regions.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-68419?


## How do I fix CVE-2026-68419?

Apply the vendor's patch.

## Is CVE-2026-68419 being exploited?

There is no known exploitation of CVE-2026-68419 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68419 and fix it if it is affected.

What it is: CVE-2026-68419 is a high-severity vulnerability in Linux, published on 10 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-2026-68419 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-2026-68419/ (Markdown: https://insights.sbomify.com/CVE-2026-68419/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68419
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68419
- OSV: https://osv.dev/vulnerability/CVE-2026-68419

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68419/
Summaries are generated and may contain mistakes; the official description above is the record.