CVE-2026-98309
Received Received - Intake

Use-After-Free in Linux Kernel DRM VC4 Driver

Publication date: 2026-10-06

Last updated on: 2026-10-06

Assigner: kernel.org

Description
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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-06
Last Modified
2026-10-06
Generated
2026-10-06
AI Q&A
2026-10-06
EPSS Evaluated
N/A
NVD
CVE-2026-98309
EUVD
EUVD-2026-93294

Affected Vendors & Products

Showing 6 associated CPEs
Vendor Product Version / Range
Linux Linux c8b75bca92cbf064b9fa125fc74a85994452e935
Linux Linux c8b75bca92cbf064b9fa125fc74a85994452e935
Linux Linux c8b75bca92cbf064b9fa125fc74a85994452e935
Linux Linux c8b75bca92cbf064b9fa125fc74a85994452e935
Linux Linux c8b75bca92cbf064b9fa125fc74a85994452e935
Linux Linux 4.4

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability is a use-after-free (UAF) issue in the Linux kernel's vc4 DRM driver. It occurs when vc4_kms_load() initializes KMS polling but fails to properly clean it up during driver unbind. The polling work continues running after the device is freed, leading to a slab-use-after-free bug.

Detection Guidance

This vulnerability is specific to the Linux kernel's vc4 DRM driver and involves a use-after-free condition during module unbind. Detection requires checking for kernel logs indicating slab-use-after-free errors related to drm_kms_helper or vc4 after unloading the vc4 module. Commands: dmesg | grep -i "KASAN\|use-after-free\|vc4\|drm_kms_helper" or journalctl -k | grep -i "KASAN\|use-after-free"

Impact Analysis

This vulnerability could cause system instability or crashes when unloading the vc4 DRM driver. It may lead to kernel panics or memory corruption, potentially allowing privilege escalation or denial-of-service conditions on affected systems.

Mitigation Strategies

Apply the kernel patch that replaces drm_kms_helper_poll_init() with drmm_kms_helper_poll_init() in the vc4 driver. Until patched, avoid unloading the vc4 module or ensure no delayed work remains active after unbind. Monitor kernel logs for related errors.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-98309. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart