# CVE-2026-99004: drm/imagination: Size page table preallocation by device address


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** BELL-CVE-2026-99004, DEBIAN-CVE-2026-99004, GHSA-862j-6x74-2p6m, UBUNTU-CVE-2026-99004

## What is CVE-2026-99004?

CVE-2026-99004 is a vulnerability in Linux, published on 23 Oct 2026. 

### Official description

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

drm/imagination: Size page table preallocation by device address

Commit 0a8224058a58 ("drm/imagination: Fix page count for page table for
map() interface") passed the device address to
pvr_mmu_op_context_create(), but the preallocation is still sized from
device_addr + sgt_offset with an exclusive end. The offset into the
object's pages has no place in a device-virtual range, and the exclusive
end allocates one table too many when the range ends on a table
boundary.

Count the tables from device_addr and the inclusive end of the range.

The new calculation does not take page table indices into account. This
fixes another issue with the previous implementation, where the
difference between start and end indices could underflow when a mapping
crossed a page table boundary. This would lead to the driver
preallocating a huge number of MMU pages, exhausting system memory and
triggering an out of memory panic.

[Alessio: add paragraph to point out OOM bug being fixed, cc stable]

## Which versions are affected by CVE-2026-99004?


## How do I fix CVE-2026-99004?

Upgrade to a fixed version.

## Is CVE-2026-99004 being exploited?

There is no known exploitation of CVE-2026-99004 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99004 and fix it if it is affected.

What it is: CVE-2026-99004 is a vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99004 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-2026-99004/ (Markdown: https://insights.sbomify.com/CVE-2026-99004/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99004
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99004
- OSV: https://osv.dev/vulnerability/CVE-2026-99004

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99004/
Summaries are generated and may contain mistakes; the official description above is the record.