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.
- 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
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)
Which versions are affected by CVE-2026-46309?
It affects 1 product.
Products include 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
Sources
Also known as BELL-CVE-2026-46309, DEBIAN-CVE-2026-46309, GHSA-vpjp-gfpq-57c9, UBUNTU-CVE-2026-46309.