# CVE-2026-80702: drm/vmwgfx: fix guest_memory_dirty bitfield clobbered as size

> A bug in the vmwgfx driver causes memory corruption by writing to the wrong field, allowing attackers to read or write past buffer boundaries.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 28 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** AZL-98051, BELL-CVE-2026-80702, DEBIAN-CVE-2026-80702, GHSA-736r-87mh-h3gr, UBUNTU-CVE-2026-80702

## What is CVE-2026-80702?

CVE-2026-80702 is a high-severity memory corruption 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: fix guest_memory_dirty bitfield clobbered as size

Two sites in vmwgfx_resource.c assign boolean literals to
res->guest_memory_size, which is an unsigned long allocation-size
field; the intended target is the adjacent res->guest_memory_dirty
bitfield.  After the assignments the field holds 0 or 1 instead of
the resource's MOB allocation size:

  - vmw_resource_release()       writes 0 (false), and
  - vmw_resource_unbind_list()   writes 1 (true).

Subsequent revalidation paths read guest_memory_size when computing
the dirty page range (vmw_bo_dirty_transfer_to_res()) and the buffer
allocation size (vmw_resource_buf_alloc()), producing zero-length
walks or wrap-around ranges that read or write past the MOB bitmap.
The dirty-tracking intent of the original code (mark the resource as
dirtied since the last sync) is also lost, since guest_memory_dirty
is never updated.

Rename both assignments to guest_memory_dirty.

## Which versions are affected by CVE-2026-80702?


## How do I fix CVE-2026-80702?

Apply the vendor's patch.

## Is CVE-2026-80702 being exploited?

There is no known exploitation of CVE-2026-80702 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80702 and fix it if it is affected.

What it is: CVE-2026-80702 is a high-severity memory corruption 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-2026-80702 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-2026-80702/ (Markdown: https://insights.sbomify.com/CVE-2026-80702/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80702
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80702
- OSV: https://osv.dev/vulnerability/CVE-2026-80702

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80702/
Summaries are generated and may contain mistakes; the official description above is the record.