CyberSecBulletin
CVE-2025-39806NVD status: Modified

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2025-39806 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 4263e5851779f7d8ebfbc9cc7d2e9b0217adba8d, 7ab7311c43ae19c66c53ccd8c5052a9072a4e338, d4e6e2680807671e1c73cd6a986b33659ce92f2b as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.24% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 4263e5851779f7d8ebfbc9cc7d2e9b0217adba8d or 7ab7311c43ae19c66c53ccd8c5052a9072a4e338 or d4e6e2680807671e1c73cd6a986b33659ce92f2b or 3055309821dd3da92888f88bad10f0324c3c89fe, whichever matches your release line, or a later version.
  2. Update SIMATIC CN 4100 to V5.0 or a later version.
  3. Update Linux Kernel to 5.15.191 or 6.1.150 or 6.6.104 or 6.11, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux7d91a0b2151a9c3b61d44c85c8eba930eddd1dd0 up to, but not including, 4263e5851779f7d8ebfbc9cc7d2e9b0217adba8d; 45ec9f17ce46417fc4eccecf388c99e81fb7fcc1 up to, but not including, 7ab7311c43ae19c66c53ccd8c5052a9072a4e338; 1d5c7d0a49ec9d8786f266ac6d1d7c4960e1787b up to, but not including, d4e6e2680807671e1c73cd6a986b33659ce92f2b; c8000deb68365b461b324d68c7ea89d730f0bb85 up to, but not including, 3055309821dd3da92888f88bad10f0324c3c89fe; c8000deb68365b461b324d68c7ea89d730f0bb85 up to, but not including, c13e95587583d018cfbcc277df7e02d41902ac5a; c8000deb68365b461b324d68c7ea89d730f0bb85 up to, but not including, 0379eb8691b9c4477da0277ae0832036ca4410b4; d189e24a42b8bd0ece3d28801d751bf66dba8e92; 5.15.168 up to, but not including, 5.15.191; and 4 more ranges4263e5851779f7d8ebfbc9cc7d2e9b0217adba8d, 7ab7311c43ae19c66c53ccd8c5052a9072a4e338, d4e6e2680807671e1c73cd6a986b33659ce92f2b, 3055309821dd3da92888f88bad10f0324c3c89fe, c13e95587583d018cfbcc277df7e02d41902ac5a, 0379eb8691b9c4477da0277ae0832036ca4410b4
SiemensSIMATIC CN 4100before V5.0V5.0
LinuxLinux Kernel5.15.168 up to, but not including, 5.15.191; 6.1.111 up to, but not including, 6.1.150; 6.6.52 up to, but not including, 6.6.104; 6.10.11 up to, but not including, 6.11; 6.11.1 up to, but not including, 6.12.45; 6.13 up to, but not including, 6.16.5; 6.11; 6.175.15.191, 6.1.150, 6.6.104, 6.11, 6.12.45, 6.16.5
DebianDebian Linux11.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighCNA
CVSS 3.17.1HighNVD

Official 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 [...]

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Out-of-bounds Read vulnerabilities

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