# CVE-2026-74424: fbcon: fix NULL pointer dereference for a console without vc_data

> A local attacker can cause a denial of service in the Linux kernel by triggering a NULL pointer dereference in the framebuffer console driver.

- **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:** 15 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** BELL-CVE-2026-74424, DEBIAN-CVE-2026-74424, GHSA-wq9g-885w-mm9h, UBUNTU-CVE-2026-74424

## What is CVE-2026-74424?

CVE-2026-74424 is a 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:

fbcon: fix NULL pointer dereference for a console without vc_data

fbcon_new_modelist() runs when a framebuffer's modelist changes. For each
console mapped to it with fb_display[i].mode set, it reads vc_cons[i].d and
passes the vc_num to fbcon_set_disp(). This assumes a console with a mode
set has a vc_data, but it can be NULL. fbcon_set_disp() sets
fb_display[i].mode before it checks vc_data, and fbcon_deinit() leaves the
mode set after the vc_data is freed. fbcon_new_modelist() then dereferences
the NULL vc_data.

Keep fb_display[i].mode set only while the console has a vc_data. Check
vc_data before setting the mode in fbcon_set_disp(), and clear the mode in
fbcon_deinit(). The existing mode check in fbcon_new_modelist() then skips
such consoles.

## Which versions are affected by CVE-2026-74424?


## How do I fix CVE-2026-74424?

Apply the vendor's patch.

## Is CVE-2026-74424 being exploited?

There is no known exploitation of CVE-2026-74424 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74424 and fix it if it is affected.

What it is: CVE-2026-74424 is a 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-2026-74424 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-2026-74424/ (Markdown: https://insights.sbomify.com/CVE-2026-74424/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74424
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74424
- OSV: https://osv.dev/vulnerability/CVE-2026-74424

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74424/
Summaries are generated and may contain mistakes; the official description above is the record.