# CVE-2026-68305: drm/xe/vf: Add drm_dev guards when detaching CCS read/write buffers

> A local attacker can trigger a kernel crash by destroying buffer objects after device unbinding, causing a NULL pointer dereference in the Xe GPU driver.

- **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-2026-68305, DEBIAN-CVE-2026-68305, GHSA-qfm9-4w8r-pq56, UBUNTU-CVE-2026-68305

## What is CVE-2026-68305?

CVE-2026-68305 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: Add drm_dev guards when detaching CCS read/write buffers

CCS read/write buffers are freed during BO destruction. In some cases,
BOs may be destroyed after the device is unbound but while the DRM
structure remains valid, leading to NULL pointer dereferences when
accessing device resources.

BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP NOPTI
CPU: 0 UID: 0 PID: 9376 Comm: xe_pat Not tainted 7.2.0-rc2+ #1 PREEMPT(lazy)
RIP: 0010:xe_sriov_vf_ccs_rw_update_bb_addr+0x4d/0xa0 [xe]
RSP: 0018:ffffcf304110b9c8 EFLAGS: 00010246
RAX: ffff8a85c38a0a00 RBX: 00000000810ef000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8a85c39c1888
RBP: ffffcf304110b9e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a85c39c1888
R13: 0000000000000000 R14: ffff8a85c39b4f28 R15: ffff8a85c3885000
FS:  0000000000000000(0000) GS:ffff8a878b809000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010314a002 CR4: 0000000000772ef0
PKRU: 55555554
Call Trace:
 <TASK>
 xe_migrate_ccs_rw_copy_clear+0x98/0x120 [xe]
 xe_sriov_vf_ccs_detach_bo+0x2c/0x60 [xe]
 xe_ttm_bo_delete_mem_notify+0xc8/0xe0 [xe]
 ttm_bo_cleanup_memtype_use+0x26/0x80 [ttm]
 ttm_bo_release+0x29e/0x2d0 [ttm]
 ttm_bo_fini+0x39/0x70 [ttm]
 xe_gem_object_free+0x1f/0x30 [xe]
 drm_gem_object_free+0x1d/0x40
 ttm_bo_vm_close+0x5f/0x90 [ttm]
 remove_vma+0x2c/0x70
 tear_down_vmas+0x63/0xf0
 exit_mmap+0x20d/0x3f0
 __mmput+0x45/0x170
 mmput+0x31/0x40
 do_exit+0x2ba/0xac0
 do_group_exit+0x2d/0xb0
 __x64_sys_exit_group+0x18/0x20
 x64_sys_call+0x14a0/0x2390
 do_syscall_64+0xdd/0x640
 ? count_memcg_events+0xea/0x240
 ? handle_mm_fault+0x1ec/0x2f0

(cherry picked from commit 1ae415a6eefe5004954a1d352b1718faca8844ef)

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-68305?


## How do I fix CVE-2026-68305?

Apply the vendor's patch.

## Is CVE-2026-68305 being exploited?

There is no known exploitation of CVE-2026-68305 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68305 and fix it if it is affected.

What it is: CVE-2026-68305 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-2026-68305 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-2026-68305/ (Markdown: https://insights.sbomify.com/CVE-2026-68305/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68305
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68305
- OSV: https://osv.dev/vulnerability/CVE-2026-68305

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68305/
Summaries are generated and may contain mistakes; the official description above is the record.