Bug 2482636 (CVE-2026-46209) - CVE-2026-46209 kernel: drm/gem: Fix inconsistent plane dimension calculation in drm_gem_fb_init_with_funcs()
Summary: CVE-2026-46209 kernel: drm/gem: Fix inconsistent plane dimension calculation ...
Keywords:
Status: NEW
Alias: CVE-2026-46209
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-28 11:06 UTC by OSIDB Bzimport
Modified: 2026-07-29 01:06 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:34911 0 None None None 2026-07-02 13:42:30 UTC
Red Hat Product Errata RHSA-2026:36018 0 None None None 2026-07-06 19:57:18 UTC
Red Hat Product Errata RHSA-2026:36348 0 None None None 2026-07-07 19:25:48 UTC
Red Hat Product Errata RHSA-2026:36349 0 None None None 2026-07-07 19:40:37 UTC
Red Hat Product Errata RHSA-2026:40068 0 None None None 2026-07-15 15:54:25 UTC
Red Hat Product Errata RHSA-2026:40760 0 None None None 2026-07-16 07:16:21 UTC
Red Hat Product Errata RHSA-2026:43231 0 None None None 2026-07-22 06:23:44 UTC
Red Hat Product Errata RHSA-2026:44385 0 None None None 2026-07-23 11:57:01 UTC
Red Hat Product Errata RHSA-2026:47632 0 None None None 2026-07-29 00:52:07 UTC
Red Hat Product Errata RHSA-2026:47633 0 None None None 2026-07-29 01:06:35 UTC

Description OSIDB Bzimport 2026-05-28 11:06:59 UTC
In the Linux kernel, the following vulnerability has been resolved:

drm/gem: Fix inconsistent plane dimension calculation in drm_gem_fb_init_with_funcs()

drm_gem_fb_init_with_funcs() computes sub-sampled plane dimensions
using plain integer division:

  unsigned int width  = mode_cmd->width  / (i ? info->hsub : 1);
  unsigned int height = mode_cmd->height / (i ? info->vsub : 1);

However, the ioctl-level framebuffer_check() in drm_framebuffer.c uses
drm_format_info_plane_width/height() which round up dimensions via
DIV_ROUND_UP(). This inconsistency corrupts the subsequent GEM object
size check for certain pixel format and dimension combinations.

For example, with NV12 (vsub=2) and a 1-pixel-tall framebuffer the
GEM size validation path sees height=0 instead of height=1. The
expression (height - 1) then wraps to UINT_MAX as an unsigned int,
causing min_size to overflow and wrap back to a small value. A tiny
GEM object therefore passes the size guard, yet when the GPU accesses
the chroma plane it will read or write memory beyond the object's
bounds.

Fix by replacing the open-coded divisions with drm_format_info_plane_width()
and drm_format_info_plane_height(), which use DIV_ROUND_UP() and match
the calculation already used in framebuffer_check().

Comment 3 errata-xmlrpc 2026-07-02 13:42:29 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:34911 https://access.redhat.com/errata/RHSA-2026:34911

Comment 4 errata-xmlrpc 2026-07-06 19:57:17 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:36018 https://access.redhat.com/errata/RHSA-2026:36018

Comment 5 errata-xmlrpc 2026-07-07 19:25:47 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:36348 https://access.redhat.com/errata/RHSA-2026:36348

Comment 6 errata-xmlrpc 2026-07-07 19:40:36 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:36349 https://access.redhat.com/errata/RHSA-2026:36349

Comment 7 errata-xmlrpc 2026-07-15 15:54:25 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

Via RHSA-2026:40068 https://access.redhat.com/errata/RHSA-2026:40068

Comment 8 errata-xmlrpc 2026-07-16 07:16:20 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2026:40760 https://access.redhat.com/errata/RHSA-2026:40760

Comment 9 errata-xmlrpc 2026-07-22 06:23:43 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Via RHSA-2026:43231 https://access.redhat.com/errata/RHSA-2026:43231

Comment 10 errata-xmlrpc 2026-07-23 11:57:00 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:44385 https://access.redhat.com/errata/RHSA-2026:44385

Comment 11 errata-xmlrpc 2026-07-29 00:52:06 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:47632 https://access.redhat.com/errata/RHSA-2026:47632

Comment 12 errata-xmlrpc 2026-07-29 01:06:34 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2026:47633 https://access.redhat.com/errata/RHSA-2026:47633


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