CVE-2026-98309 PUBLISHED

drm/vc4: Use managed KMS polling to fix UAF on unbind

Assigner: Linux
Reserved: 25.09.2026 Published: 06.10.2026 Updated: 06.10.2026

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

drm/vc4: Use managed KMS polling to fix UAF on unbind

vc4_kms_load() calls drm_kms_helper_poll_init() but the driver provides no matching drm_kms_helper_poll_fini(). The output poll work stays scheduled after unbind and runs on the freed drm_device:

# modprobe vc4; rmmod vc4; sleep 10 BUG: KASAN: slab-use-after-free in delayed_work_timer_fn BUG: KASAN: slab-use-after-free in drm_client_dev_hotplug [drm] Workqueue: events output_poll_execute [drm_kms_helper] Allocated by task 171: __devm_drm_dev_alloc Freed by task 262 (rmmod): drm_dev_put / component_del

Use drmm_kms_helper_poll_init() so polling is finalized with the device, as other drivers do.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from c8b75bca92cbf064b9fa125fc74a85994452e935 to b6beee927e7f4e3142032ff91b2d0417cdddc0f6 (excl.)
  • affected from c8b75bca92cbf064b9fa125fc74a85994452e935 to cf0c4432bda37b02e7d430ff5017228ceb7caf0c (excl.)
  • affected from c8b75bca92cbf064b9fa125fc74a85994452e935 to ee507691c18f9fee5d4751e295ab9a7ff31d59ae (excl.)
  • affected from c8b75bca92cbf064b9fa125fc74a85994452e935 to 7f9780df677370a19b4ec9764f13b1b82073e0d9 (excl.)
  • affected from c8b75bca92cbf064b9fa125fc74a85994452e935 to 073a30d75f309812ed61af134f24ffef4107b13a (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 4.4 is affected
  • unaffected from 0 to 4.4 (excl.)
  • unaffected from 6.6.158 to 6.6.* (incl.)
  • unaffected from 6.12.112 to 6.12.* (incl.)
  • unaffected from 6.18.54 to 6.18.* (incl.)
  • unaffected from 7.2.8 to 7.2.* (incl.)
  • unaffected from 7.3-rc4 to * (incl.)

References