# CVE-2025-68816: net/mlx5: fw_tracer, Validate format string parameters

> Malicious firmware can send unsafe format strings to the mlx5 tracer, causing kernel crashes or potential code execution.

- **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:** 13 Jan 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-74430, BELL-CVE-2025-68816, DEBIAN-CVE-2025-68816, GHSA-446v-vm34-72r6, ROOT-OS-DEBIAN-11-CVE-2025-68816, ROOT-OS-DEBIAN-12-CVE-2025-68816, ROOT-OS-DEBIAN-13-CVE-2025-68816, ROOT-OS-UBUNTU-2204-CVE-2025-68816, ROOT-OS-UBUNTU-2404-CVE-2025-68816, UBUNTU-CVE-2025-68816

## What is CVE-2025-68816?

CVE-2025-68816 is a memory corruption vulnerability in Linux, published on 13 Jan 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:

net/mlx5: fw_tracer, Validate format string parameters

Add validation for format string parameters in the firmware tracer to
prevent potential security vulnerabilities and crashes from malformed
format strings received from firmware.

The firmware tracer receives format strings from the device firmware and
uses them to format trace messages. Without proper validation, bad
firmware could provide format strings with invalid format specifiers
(e.g., %s, %p, %n) that could lead to crashes, or other undefined
behavior.

Add mlx5_tracer_validate_params() to validate that all format specifiers
in trace strings are limited to safe integer/hex formats (%x, %d, %i,
%u, %llx, %lx, etc.). Reject strings containing other format types that
could be used to access arbitrary memory or cause crashes.
Invalid format strings are added to the trace output for visibility with
"BAD_FORMAT: " prefix.

Weakness: CWE-134 (Use of Externally-Controlled Format String)

## Which versions are affected by CVE-2025-68816?


## How do I fix CVE-2025-68816?

Apply the vendor's patch.

## Is CVE-2025-68816 being exploited?

There is no known exploitation of CVE-2025-68816 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68816 and fix it if it is affected.

What it is: CVE-2025-68816 is a memory corruption vulnerability in Linux, published on 13 Jan 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-2025-68816 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-2025-68816/ (Markdown: https://insights.sbomify.com/CVE-2025-68816/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68816
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68816
- OSV: https://osv.dev/vulnerability/CVE-2025-68816

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68816/
Summaries are generated and may contain mistakes; the official description above is the record.