CVE-2025-39806

01/Description

In the Linux kernel, the following vulnerability has been resolved: HID: multitouch: fix slab out-of-bounds access in mt_report_fixup() A malicious HID device can trigger a slab out-of-bounds during mt_report_fixup() by passing in report descriptor smaller than 607 bytes. mt_report_fixup() attempts to patch byte offset 607 of the descriptor with 0x25 by first checking if byte offset 607 is 0x15 however it lacks bounds checks to verify if the descriptor is big enough before conducting this check. Fix this bug by ensuring the descriptor size is at least 608 bytes before accessing it. Below is the KASAN splat after the out of bounds access happens: [ 13.671954] ================================================================== [ 13.672667] BUG: KASAN: slab-out-of-bounds in mt_report_fixup+0x103/0x110 [ 13.673297] Read of size 1 at addr ffff888103df39df by task kworker/0:1/10 [ 13.673297] [ 13.673297] CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted 6.15.0-00005-gec5d573d83f4-dirty #3 [ 13.673297] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/04 [ 13.673297] Call Trace: [ 13.673297] <TASK> [ 13.673297] dump_stack_lvl+0x5f/0x80 [ 13.673297] print_report+0xd1/0x660 [ 13.673297] kasan_report+0xe5/0x120 [ 13.673297] __asan_report_load1_noabort+0x18/0x20 [ 13.673297] mt_report_fixup+0x103/0x110 [ 13.673297] hid_open_report+0x1ef/0x810 [ 13.673297] mt_probe+0x422/0x960 [ 13.673297] hid_device_probe+0x2e2/0x6f0 [ 13.673297] really_probe+0x1c6/0x6b0 [ 13.673297] __driver_probe_device+0x24f/0x310 [ 13.673297] driver_probe_device+0x4e/0x220 [ 13.673297] __device_attach_driver+0x169/0x320 [ 13.673297] bus_for_each_drv+0x11d/0x1b0 [ 13.673297] __device_attach+0x1b8/0x3e0 [ 13.673297] device_initial_probe+0x12/0x20 [ 13.673297] bus_probe_device+0x13d/0x180 [ 13.673297] device_add+0xe3a/0x1670 [ 13.673297] hid_add_device+0x31d/0xa40 [...]

02/Affected products

linux: linux kernel; debian: debian linux

03/References8

• git.kernel.org/stable/c/0379eb8691b9c4477da0277ae0832036ca4410b4 Patch
• git.kernel.org/stable/c/3055309821dd3da92888f88bad10f0324c3c89fe Patch
• git.kernel.org/stable/c/4263e5851779f7d8ebfbc9cc7d2e9b0217adba8d Patch
• git.kernel.org/stable/c/7ab7311c43ae19c66c53ccd8c5052a9072a4e338 Patch
• git.kernel.org/stable/c/c13e95587583d018cfbcc277df7e02d41902ac5a Patch
• git.kernel.org/stable/c/d4e6e2680807671e1c73cd6a986b33659ce92f2b Patch
• lists.debian.org/debian-lts-announce/2025/10/msg00008.html Third Party Advisory
• cert-portal.siemens.com/productcert/html/ssa-032379.html