# CVE-2026-23467: drm/i915/dmc: Fix an unlikely NULL pointer deference at probe

> A null pointer dereference in the Intel i915 graphics driver can cause a kernel crash during system boot if DC6 power state is unexpectedly enabled.

- **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:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Apr 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-23467, DEBIAN-CVE-2026-23467, GHSA-2qjv-hmp6-mh5w, UBUNTU-CVE-2026-23467

## What is CVE-2026-23467?

CVE-2026-23467 is a medium-severity vulnerability in Linux kernel, published on 3 Apr 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:

drm/i915/dmc: Fix an unlikely NULL pointer deference at probe

intel_dmc_update_dc6_allowed_count() oopses when DMC hasn't been
initialized, and dmc is thus NULL.

That would be the case when the call path is
intel_power_domains_init_hw() -> {skl,bxt,icl}_display_core_init() ->
gen9_set_dc_state() -> intel_dmc_update_dc6_allowed_count(), as
intel_power_domains_init_hw() is called *before* intel_dmc_init().

However, gen9_set_dc_state() calls intel_dmc_update_dc6_allowed_count()
conditionally, depending on the current and target DC states. At probe,
the target is disabled, but if DC6 is enabled, the function is called,
and an oops follows. Apparently it's quite unlikely that DC6 is enabled
at probe, as we haven't seen this failure mode before.

It is also strange to have DC6 enabled at boot, since that would require
the DMC firmware (loaded by BIOS); the BIOS loading the DMC firmware and
the driver stopping / reprogramming the firmware is a poorly specified
sequence and as such unlikely an intentional BIOS behaviour. It's more
likely that BIOS is leaving an unintentionally enabled DC6 HW state
behind (without actually loading the required DMC firmware for this).

The tracking of the DC6 allowed counter only works if starting /
stopping the counter depends on the _SW_ DC6 state vs. the current _HW_
DC6 state (since stopping the counter requires the DC5 counter captured
when the counter was started). Thus, using the HW DC6 state is incorrect
and it also leads to the above oops. Fix both issues by using the SW DC6
state for the tracking.

This is v2 of the fix originally sent by Jani, updated based on the
first Link: discussion below.

(cherry picked from commit 2344b93af8eb5da5d496b4e0529d35f0f559eaf0)

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-23467?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23467?

Apply the vendor's patch.

## Is CVE-2026-23467 being exploited?

There is no known exploitation of CVE-2026-23467 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-2026-23467 and fix it if it is affected.

What it is: CVE-2026-23467 is a medium-severity vulnerability in Linux kernel, published on 3 Apr 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-2026-23467 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-2026-23467/ (Markdown: https://insights.sbomify.com/CVE-2026-23467/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23467
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23467
- OSV: https://osv.dev/vulnerability/CVE-2026-23467

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23467/
Summaries are generated and may contain mistakes; the official description above is the record.