# CVE-2026-99007: drm/fb-helper: defer setup when fbdev_probe() fails, not just on -EAGAIN


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** AZL-110849, BELL-CVE-2026-99007, DEBIAN-CVE-2026-99007, GHSA-g687-j9p7-p4rx, UBUNTU-CVE-2026-99007

## What is CVE-2026-99007?

CVE-2026-99007 is a vulnerability in Linux, published on 23 Oct 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

drm/fb-helper: defer setup when fbdev_probe() fails, not just on -EAGAIN

__drm_fb_helper_initial_config_and_unlock() calls
drm_client_modeset_probe() first, which already fills in each
mode_set->mode/num_connectors for every connected output, and only
afterwards calls drm_fb_helper_single_fb_probe() to create
fb_helper->fb and wire it into those mode_sets via
drm_setup_crtcs_fb().

If drm_fb_helper_single_fb_probe() fails with anything other than
-EAGAIN (e.g. dev->driver->fbdev_probe() itself fails), the function
bails out before drm_setup_crtcs_fb() runs and before setting
fb_helper->deferred_setup. The client is left with mode_sets that
have a mode and connectors but mode_set->fb == NULL, and nothing
marks this fb_helper as needing a retry.

__drm_fb_helper_restore_fbdev_mode_unlocked() only skips committing
when fb_helper->deferred_setup is set, so a later .restore() call
(drm_lastclose() on process exit, in this report) commits the stale
mode_set through drm_client_modeset_commit() ->
drm_client_modeset_commit_atomic() -> __drm_atomic_helper_set_config(),
which hits WARN_ON(!set->fb).

Mark fb_helper->deferred_setup on any drm_fb_helper_single_fb_probe()
failure, not just -EAGAIN, so restore keeps skipping the commit until
a later hotplug event successfully re-probes and re-populates
mode_set->fb. The real error code is still returned to the caller
unchanged.

## Which versions are affected by CVE-2026-99007?


## How do I fix CVE-2026-99007?

Upgrade to a fixed version.

## Is CVE-2026-99007 being exploited?

There is no known exploitation of CVE-2026-99007 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99007 and fix it if it is affected.

What it is: CVE-2026-99007 is a vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99007 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-2026-99007/ (Markdown: https://insights.sbomify.com/CVE-2026-99007/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99007
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99007
- OSV: https://osv.dev/vulnerability/CVE-2026-99007

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99007/
Summaries are generated and may contain mistakes; the official description above is the record.