Bug 2461562 (CVE-2026-31571)

Summary: CVE-2026-31571 kernel: drm/i915: Unlink NV12 planes earlier
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `drm/i915` component. A local user can exploit this by configuring a graphics plane, previously designated for Y-component data (Y plane), as a standard plane. This incorrect configuration leads to a race condition where the `unlink_nv12_plane()` function improperly clears parts of the plane's state after it has been set by `plane_atomic_check()`. The consequence is data corruption within the graphics plane state, which can result in system instability or a denial of service (DoS).
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Description OSIDB Bzimport 2026-04-24 15:08:37 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/i915: Unlink NV12 planes earlier

unlink_nv12_plane() will clobber parts of the plane state
potentially already set up by plane_atomic_check(), so we
must make sure not to call the two in the wrong order.
The problem happens when a plane previously selected as
a Y plane is now configured as a normal plane by user space.
plane_atomic_check() will first compute the proper plane
state based on the userspace request, and unlink_nv12_plane()
later clears some of the state.

This used to work on account of unlink_nv12_plane() skipping
the state clearing based on the plane visibility. But I removed
that check, thinking it was an impossible situation. Now when
that situation happens unlink_nv12_plane() will just WARN
and proceed to clobber the state.

Rather than reverting to the old way of doing things, I think
it's more clear if we unlink the NV12 planes before we even
compute the new plane state.

(cherry picked from commit 017ecd04985573eeeb0745fa2c23896fb22ee0cc)
Comment 1 Keith Grant 2026-04-24 18:03:48 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042402-CVE-2026-31571-41f9@gregkh/T