# CVE-2026-68384: drm/xe/vf: Fix VF CCS attach/detach race with in-flight BO moves

> A race condition in the Linux kernel's Xe GPU driver allows VF migration events to observe inconsistent CCS metadata, potentially leading to data corruption or exposure.

- **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:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68384, DEBIAN-CVE-2026-68384, GHSA-hr8j-ghcq-qgrr, UBUNTU-CVE-2026-68384

## What is CVE-2026-68384?

CVE-2026-68384 is a high-severity vulnerability in Linux, published on 10 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/xe/vf: Fix VF CCS attach/detach race with in-flight BO moves

xe_bo_move() attaches VF CCS read/write batch buffers (BBs) to a BO
after it transitions NULL/SYSTEM -> TT, and detaches them after it
transitions TT -> SYSTEM. Both operations were done synchronously on
the CPU immediately after building the move's copy/clear fence,
without waiting for that fence to signal. This creates two races with
VF migration:

- Attach happens too late relative to the copy job it is meant to
  protect. If the copy job is submitted before the CCS BBs are
  attached, a VF migration event that pauses execution mid-copy can
  observe partially copied CCS metadata without the attach state
  needed to correctly save/restore it.

- Detach happens too early relative to the copy job that moves data
  out of TT. The CCS BBs are torn down right after the copy fence is
  obtained, while the actual blit may still be in flight. A VF
  migration event that pauses execution mid-copy can then race the
  save/restore path against the still-running blit, and the CCS BBs
  it would need to make sense of the paused state have already been
  removed.

Fix both races:

- Move the attach call to before the copy/clear job is submitted, so
  the CCS BBs are already registered by the time the copy runs. On
  attach failure, unwind and bail out of the move. xe_migrate_ccs_rw_copy()
  now takes the destination resource explicitly, since bo->ttm.resource
  is not updated to the new resource until after the move commits.

- Detach only after explicitly waiting for the copy fence to signal,
  instead of tearing down the CCS BBs immediately after obtaining it.

While here, also fix xe_sriov_vf_ccs_attach_bo() to properly unwind and
propagate errors: the per-context loop previously never broke out on
error, silently discarding earlier failures. Unwind by clearing each
attached context directly via xe_migrate_ccs_rw_copy_clear() instead of
reusing xe_sriov_vf_ccs_detach_bo(), which requires both contexts to be
attached before it will clean up either one.

(cherry picked from commit d45ad0aa7a1eb5d7288b5ed948b05695611dc39e)

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-68384?


## How do I fix CVE-2026-68384?

Apply the vendor's patch.

## Is CVE-2026-68384 being exploited?

There is no known exploitation of CVE-2026-68384 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68384 and fix it if it is affected.

What it is: CVE-2026-68384 is a high-severity vulnerability in Linux, published on 10 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-2026-68384 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-2026-68384/ (Markdown: https://insights.sbomify.com/CVE-2026-68384/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68384
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68384
- OSV: https://osv.dev/vulnerability/CVE-2026-68384

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68384/
Summaries are generated and may contain mistakes; the official description above is the record.