CVE-2026-52966: drm: Replace old pointer to new idr

CVE-2026-52966: drm: Replace old pointer to new idr

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

drm: Replace old pointer to new idr

Commit 5e28b7b94408 introduced a logical error by failing to replace the
newly generated IDR pointer to old id's pointer at the correct location
within the "change handle" logic; this resulted in the issue reported by
syzbot [1].

Specifically, the new IDR object pointer is intended to replace the original
id's pointer during the normal execution flow.

Additionally, an unnecessary conditional check for the ret exit path has
been removed.

[1]
!RB_EMPTY_ROOT(&prime_fpriv->dmabufs)
WARNING: drivers/gpu/drm/drm_prime.c:224 at drm_prime_destroy_file_private+0x48/0x60 drivers/gpu/drm/drm_prime.c:224, CPU#0: syz.0.17/5833
Call Trace:
 drm_file_free.part.0+0x7e6/0xcc0 drivers/gpu/drm/drm_file.c:269
 drm_file_free drivers/gpu/drm/drm_file.c:237 [inline]
 drm_close_helper.isra.0+0x186/0x200 drivers/gpu/drm/drm_file.c:290
 drm_release+0x1ab/0x360 drivers/gpu/drm/drm_file.c:438

The Linux kernel CVE team has assigned CVE-2026-52966 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.18.32 with commit 672464dd53231509c9c771110798c56d4660e19e and fixed in 6.18.33 with commit 318b995cffcfcaa69a234d28123a3f4ae186a9df
	Issue introduced in 7.0.9 with commit 61bd96d3e5472c253f9c1ab77608f0c8aaa9d025 and fixed in 7.0.10 with commit 38f12d0e10d83b66fa1466400d876a3a8da31542

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-52966
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/drm_gem.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/318b995cffcfcaa69a234d28123a3f4ae186a9df
	https://git.kernel.org/stable/c/38f12d0e10d83b66fa1466400d876a3a8da31542
	https://git.kernel.org/stable/c/dc366607c41c45fd0ae6f3db090f31dd611b644a