CVE-2025-39711 — media: ivsc: Fix crash at shutdown due to missing mei_cldev_disable() calls

Affected: Linux

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

media: ivsc: Fix crash at shutdown due to missing mei_cldev_disable() calls

Both the ACE and CSI driver are missing a mei_cldev_disable() call in their remove() function.

This causes the mei_cl client to stay part of the mei_device->file_list list even though its memory is freed by mei_cl_bus_dev_release() calling kfree(cldev->cl).

This leads to a use-after-free when mei_vsc_remove() runs mei_stop() which first removes all mei bus devices calling mei_ace_remove() and mei_csi_remove() followed by mei_cl_bus_dev_release() and then calls mei_cl_all_disconnect() which walks over mei_device->file_list dereferecing the just freed cldev->cl.

And mei_vsc_remove() it self is run at shutdown because of the platform_device_unregister(tp->pdev) in vsc_tp_shutdown()

When building a kernel with KASAN this leads to the following KASAN report:

[ 106.634504] ================================================================== [ 106.634623] BUG: KASAN: slab-use-after-free in mei_cl_set_disconnected (drivers/misc/mei/client.c:783) mei [ 106.634683] Read of size 4 at addr ffff88819cb62018 by task systemd-shutdow/1 [ 106.634729] [ 106.634767] Tainted: [E]=UNSIGNED_MODULE [ 106.634770] Hardware name: Dell Inc. XPS 16 9640/09CK4V, BIOS 1.12.0 02/10/2025 [ 106.634773] Call Trace: [ 106.634777] <TASK> ... [ 106.634871] kasan_report (mm/kasan/report.c:221 mm/kasan/report.c:636) [ 106.634901] mei_cl_set_disconnected (drivers/mis…

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CVE-2025-39711 — media: ivsc: Fix crash at shutdown due to missing mei_cldev_disable() calls