# CVE-2026-90416: RDMA/mlx5: Fix stack out-of-bounds read in cc_params debugfs

> A local attacker with debugfs access can trigger a stack out-of-bounds read in the RDMA mlx5 driver, potentially leaking kernel memory.

- **Severity:** Not scored
- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-103044, BELL-CVE-2026-90416, DEBIAN-CVE-2026-90416, GHSA-5qwc-6c47-m348, UBUNTU-CVE-2026-90416

## What is CVE-2026-90416?

CVE-2026-90416 is a vulnerability in Linux, published on 17 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/mlx5: Fix stack out-of-bounds read in cc_params debugfs

get_param() reads a congestion parameter as a u32 but formats it with the
signed "%d" into an 11-byte stack buffer. A value with bit 31 set, such as
0x80000000, renders as "-2147483648\n" whose full length is 12. snprintf()
stores only 11 bytes yet returns 12, so simple_read_from_buffer() treats 12
bytes as valid and reads one byte past lbuf[].

Size the buffer for the widest unsigned decimal, format with "%u" to match
the u32, and use scnprintf() so the length passed to
simple_read_from_buffer() reflects the bytes actually stored.

## Which versions are affected by CVE-2026-90416?


## How do I fix CVE-2026-90416?

Apply the vendor's patch.

## Is CVE-2026-90416 being exploited?

There is no known exploitation of CVE-2026-90416 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90416 and fix it if it is affected.

What it is: CVE-2026-90416 is a vulnerability in Linux, published on 17 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-2026-90416 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-2026-90416/ (Markdown: https://insights.sbomify.com/CVE-2026-90416/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90416
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90416
- OSV: https://osv.dev/vulnerability/CVE-2026-90416

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90416/
Summaries are generated and may contain mistakes; the official description above is the record.