# CVE-2026-46309: drm/xe/uapi: Reject coh_none PAT index for CPU cached memory in madvise

> A local attacker can leak sensitive data from previously freed pages of other processes by exploiting a cache coherency flaw in the Intel Xe GPU driver.

- **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/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:** 8 Jun 2026
- **Updated:** 15 Jul 2026
- **Also known as:** BELL-CVE-2026-46309, DEBIAN-CVE-2026-46309, GHSA-vpjp-gfpq-57c9, UBUNTU-CVE-2026-46309

## What is CVE-2026-46309?

CVE-2026-46309 is a high-severity vulnerability in Linux kernel, published on 8 Jun 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/uapi: Reject coh_none PAT index for CPU cached memory in madvise

Add validation in xe_vm_madvise_ioctl() to reject PAT indices with
XE_COH_NONE coherency mode when applied to CPU cached memory.

Using coh_none with CPU cached buffers is a security issue. When the
kernel clears pages before reallocation, the clear operation stays in
CPU cache (dirty). GPU with coh_none can bypass CPU caches and read
stale sensitive data directly from DRAM, potentially leaking data from
previously freed pages of other processes.

This aligns with the existing validation in vm_bind path
(xe_vm_bind_ioctl_validate_bo).

v2(Matthew brost)
- Add fixes
- Move one debug print to better place

v3(Matthew Auld)
- Should be drm/xe/uapi
- More Cc

v4(Shuicheng Lin)
- Fix kmem leak issues by the way

v5
- Remove kmem leak because it has been merged by another patch

v6
- Remove the fix which is not related to current fix

v7
- No change

v8
- Rebase

v9
- Limit the restrictions to iGPU

v10
- No change

(cherry picked from commit 016ccdb674b8c899940b3944952c96a6a490d10a)

Weakness: CWE-524 (Use of Cache Containing Sensitive Information), CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-46309?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46309?

Apply the vendor's patch.

## Is CVE-2026-46309 being exploited?

There is no known exploitation of CVE-2026-46309 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-46309 and fix it if it is affected.

What it is: CVE-2026-46309 is a high-severity vulnerability in Linux kernel, published on 8 Jun 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-2026-46309 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-46309/ (Markdown: https://insights.sbomify.com/CVE-2026-46309/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46309
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46309
- OSV: https://osv.dev/vulnerability/CVE-2026-46309

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46309/
Summaries are generated and may contain mistakes; the official description above is the record.