# CVE-2026-98094: staging: fbtft: make dirty_lock IRQ-safe

> A race condition in the fbtft staging driver can cause a deadlock when printing logs, leading to a system denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104595, BELL-CVE-2026-98094, DEBIAN-CVE-2026-98094, GHSA-5wg8-22v7-6q2c, UBUNTU-CVE-2026-98094

## What is CVE-2026-98094?

CVE-2026-98094 is a medium-severity vulnerability in Linux kernel, published on 25 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:

staging: fbtft: make dirty_lock IRQ-safe

fbtft_mkdirty() can be reached from the fbcon rendering path while
processing printk() in hardirq context. Meanwhile, dirty_lock is also
taken by fbtft_deferred_io() in workqueue context with local interrupts
enabled.

Lockdep reports a possible IRQ lock inversion involving dirty_lock and
console_owner. A hardirq can interrupt a CPU holding dirty_lock and
enter the console rendering path, which can attempt to acquire
dirty_lock again.

The following lockdep report was observed on an RK3566 system with
CONFIG_PROVE_LOCKING enabled:

  WARNING: possible irq lock inversion dependency detected
  swapper/2/0 just changed the state of lock:
  (console_owner){-...}-{0:0}
  but this lock took another, HARDIRQ-unsafe lock in the past:
  (&par->dirty_lock){+.+.}-{2:2}

  CPU0                    CPU1
  ----                    ----
  lock(&par->dirty_lock);
                         local_irq_disable();
                         lock(console_owner);
                         lock(&par->dirty_lock);
  <Interrupt>
    lock(console_owner);

  *** DEADLOCK ***

Use spin_lock_irqsave() for fbtft_mkdirty() and spin_lock_irq() for
fbtft_deferred_io(). They only access the dirty line range, so the
IRQ-off regions remain short.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-98094?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-98094?

Apply the vendor's patch.

## Is CVE-2026-98094 being exploited?

There is no known exploitation of CVE-2026-98094 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98094 and fix it if it is affected.

What it is: CVE-2026-98094 is a medium-severity vulnerability in Linux kernel, published on 25 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-2026-98094 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-98094/ (Markdown: https://insights.sbomify.com/CVE-2026-98094/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98094
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98094
- OSV: https://osv.dev/vulnerability/CVE-2026-98094

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98094/
Summaries are generated and may contain mistakes; the official description above is the record.