# CVE-2026-80701: drm/vmwgfx: enforce cursor size limits for MOB cursors

> A local attacker with DRM master access can trigger a kernel null pointer dereference and system crash by requesting oversized cursors in the vmwgfx 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:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** BELL-CVE-2026-80701, DEBIAN-CVE-2026-80701, GHSA-xr66-5v48-7crq, UBUNTU-CVE-2026-80701

## What is CVE-2026-80701?

CVE-2026-80701 is a vulnerability in Linux, published on 28 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:

drm/vmwgfx: enforce cursor size limits for MOB cursors

vmw_cursor_plane_atomic_check() bounds cursor width and height only
on the legacy update path; the SVGA_CAP2_CURSOR_MOB path -- the
default on modern hosts -- accepts any size.  When the requested size
exceeds SVGA_REG_CURSOR_MAX_DIMENSION or SVGA_REG_MOB_MAX_SIZE,
vmw_cursor_mob_get() returns -EINVAL and leaves vps->cursor.mob NULL.
Its return value is then discarded in vmw_cursor_plane_prepare_fb(),
so the subsequent vmw_cursor_update_mob() calls
vmw_bo_map_and_cache(NULL) and oopses inside
vmw_bo_map_and_cache_size() on the tbo.base.size load.

Reachable from any DRM master via DRM_IOCTL_MODE_CURSOR2 with a
sufficiently large width or height (e.g. cursor_max_dim + 1).

Reject oversized cursors in atomic_check for both MOB-backed cursor
update types.  The MOB byte-size limit only applies to the
SVGA_CAP2_CURSOR_MOB path (vmw_cursor_mob_size() returns 0 for
GB_ONLY); compute the required MOB size in 64-bit to avoid overflow
when very large dimensions are requested.

In prepare_fb only call vmw_cursor_mob_get()/_map() for
VMW_CURSOR_UPDATE_MOB -- the GB_ONLY path uses bo->map.virtual
directly and would otherwise be silently downgraded to NONE on hosts
without SVGA_CAP2_CURSOR_MOB (where vmw_cursor_mob_get() always
returns -EINVAL).  Degrade the update to NONE if vmw_cursor_mob_get()
or vmw_cursor_mob_map() fails so the update path does not run with a
NULL backing MOB.

## Which versions are affected by CVE-2026-80701?


## How do I fix CVE-2026-80701?

Apply the vendor's patch.

## Is CVE-2026-80701 being exploited?

There is no known exploitation of CVE-2026-80701 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80701 and fix it if it is affected.

What it is: CVE-2026-80701 is a vulnerability in Linux, published on 28 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-2026-80701 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-2026-80701/ (Markdown: https://insights.sbomify.com/CVE-2026-80701/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80701
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80701
- OSV: https://osv.dev/vulnerability/CVE-2026-80701

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80701/
Summaries are generated and may contain mistakes; the official description above is the record.