Upstream information

CVE-2026-74640 at MITRE

Description

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

ALSA: FCP: fix OOB write in fcp_meter_ctl_get()

fcp_ioctl_set_meter_map() bounds the user-supplied Level Meter map size
by the driver's own limit of 255

if (map.map_size < 1 || map.map_size > 255 ||
map.meter_slots < 1 || map.meter_slots > 255)
return -EINVAL;

and passes it to fcp_add_new_ctl() as the control's channel count, where
it is stored as elem->channels.

Every control read writes into struct snd_ctl_elem_value, whose integer
array is declared long value[128], so the limit is 128, not 255.
fcp_meter_ctl_get() stores one 64-bit word per channel into that array
with no bound of its own:

for (i = 0; i < elem->channels; i++) {
int idx = private->meter_level_map[i];
int value = idx < 0 ? 0 : le32_to_cpu(resp[idx]);

ucontrol->value.integer.value[i] = value;
}

snd_ctl_elem_read_user() serves that object from
memdup_user(_control, sizeof(*control)), 1224 bytes on LP64 out of
kmalloc-2048. offsetof(struct snd_ctl_elem_value, value) is 72, so
element i is written at byte 72 + 8 * i and element 144 already lands
past the allocation. At map_size 255 the last store ends at byte 2112,
888 bytes past the object and 64 bytes into the adjacent slab object.
The stored words come from the device and meter_level_map[] selects
which word lands in which slot, so extent and contents are both
controlled.

The core does not catch this. snd_ctl_check_elem_info() is reached only
from __snd_ctl_elem_info(), which snd_ctl_elem_read() calls under
CONFIG_SND_CTL_DEBUG; without that option snd_ctl_skip_validation() is a
compile-time true. __snd_ctl_add_replace() validates kcontrol->count and
never inspects elem->channels.

Installing an oversized map needs CAP_SYS_RAWIO, but the control outlives
the hwdep descriptor that created it, so the out-of-bounds stores are
issued by any process able to read controls on /dev/snd/controlC0.

KASAN on 7.2.0-rc5 (arm64), triggered by an unprivileged control read:

BUG: KASAN: slab-out-of-bounds in fcp_meter_ctl_get
Write of size 8 at addr ffff000017af04c8 by task fcp_trigger/185
__asan_store8
fcp_meter_ctl_get
snd_ctl_elem_read
snd_ctl_ioctl
Allocated by task 185:
memdup_user
snd_ctl_ioctl
The buggy address is located 0 bytes to the right of
allocated 1224-byte region [ffff000017af0000, ffff000017af04c8)

Bound the map size by the ABI limit rather than by 255, and bound the
store loop at the sink so it cannot run past the value array whatever
elem->channels holds.

Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

SUSE information

Overall state of this security issue: New

This issue is currently rated as having not set severity.

Note from the SUSE Security Team on the kernel-default package

SUSE will no longer fix all CVEs in the Linux Kernel anymore, but declare some bug classes as won't fix. Please refer to TID 21496 for more details.

No SUSE Bugzilla entries cross referenced.

No SUSE Security Announcements cross referenced.


Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise Desktop 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Desktop 15 SP7 kernel-source Analysis
SUSE Linux Enterprise High Availability Extension 15 SP7 kernel-default Analysis
SUSE Linux Enterprise High Availability Extension 15 SP7 kernel-source Analysis
SUSE Linux Enterprise High Availability Extension 16.0 kernel-default Analysis
SUSE Linux Enterprise High Availability Extension 16.0 kernel-source Analysis
SUSE Linux Enterprise High Availability Extension 16.1 kernel-default Analysis
SUSE Linux Enterprise High Availability Extension 16.1 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP7 kernel-default Analysis
SUSE Linux Enterprise High Performance Computing 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Live Patching 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Live Patching 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Micro 5.3 kernel-default Analysis
SUSE Linux Enterprise Micro 5.3 kernel-rt Analysis
SUSE Linux Enterprise Micro 5.3 kernel-source Analysis
SUSE Linux Enterprise Micro 5.3 kernel-source-rt Analysis
SUSE Linux Enterprise Micro 5.4 kernel-default Analysis
SUSE Linux Enterprise Micro 5.4 kernel-rt Analysis
SUSE Linux Enterprise Micro 5.4 kernel-source Analysis
SUSE Linux Enterprise Micro 5.4 kernel-source-rt Analysis
SUSE Linux Enterprise Micro 5.5 kernel-default Analysis
SUSE Linux Enterprise Micro 5.5 kernel-source Analysis
SUSE Linux Enterprise Micro 5.5 kernel-source-rt Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP7 kernel-source-rt Analysis
SUSE Linux Enterprise Server 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Server 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Server 16.0 kernel-default Analysis
SUSE Linux Enterprise Server 16.0 kernel-source Analysis
SUSE Linux Enterprise Server 16.1 kernel-default Analysis
SUSE Linux Enterprise Server 16.1 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Server for SAP applications 16.0 kernel-default Analysis
SUSE Linux Enterprise Server for SAP applications 16.0 kernel-source Analysis
SUSE Linux Enterprise Server for SAP applications 16.1 kernel-default Analysis
SUSE Linux Enterprise Server for SAP applications 16.1 kernel-source Analysis
SUSE Linux Enterprise Workstation Extension 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Workstation Extension 15 SP7 kernel-source Analysis
SUSE Linux Micro 6.0 kernel-default Analysis
SUSE Linux Micro 6.0 kernel-source Analysis
SUSE Linux Micro 6.0 kernel-source-rt Analysis
SUSE Linux Micro 6.1 kernel-default Analysis
SUSE Linux Micro 6.1 kernel-source Analysis
SUSE Linux Micro 6.1 kernel-source-rt Analysis
SUSE Linux Micro 6.2 kernel-default Analysis
SUSE Linux Micro 6.2 kernel-source Analysis
SUSE Linux Micro Extras 6.0 kernel-default Analysis
SUSE Linux Micro Extras 6.0 kernel-source Analysis
SUSE Linux Micro Extras 6.0 kernel-source-rt Analysis
SUSE Linux Micro Extras 6.1 kernel-default Analysis
SUSE Linux Micro Extras 6.1 kernel-source Analysis
SUSE Real Time Module 15 SP7 kernel-source-rt Analysis
openSUSE Leap 16.0 kernel-source Analysis
Products under Long Term Service Pack support and receiving important and critical security fixes.
SUSE Linux Enterprise High Performance Computing 12 SP5 kernel-default Analysis
SUSE Linux Enterprise High Performance Computing 12 SP5 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS kernel-default Analysis
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP5 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-default Analysis
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP6 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP6 kernel-source Analysis
SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE kernel-default Analysis
SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE kernel-source Analysis
SUSE Linux Enterprise Server 12 SP5 kernel-source Analysis
SUSE Linux Enterprise Server 12 SP5-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 12 SP5-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 12 SP5-LTSS Extended Security kernel-default Analysis
SUSE Linux Enterprise Server 12 SP5-LTSS Extended Security kernel-source Analysis
SUSE Linux Enterprise Server 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP4-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP4-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP5-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP5-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP6 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP6-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP6-LTSS kernel-source Analysis
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP4 kernel-default Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-default Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-default Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-source Analysis
SUSE Manager Proxy 4.3 kernel-source Analysis
SUSE Manager Proxy LTS 4.3 kernel-source Analysis
SUSE Manager Retail Branch Server 4.3 kernel-source Analysis
SUSE Manager Retail Branch Server LTS 4.3 kernel-source Analysis
SUSE Manager Server 4.3 kernel-source Analysis
SUSE Manager Server LTS 4.3 kernel-source Analysis
Products past their end of life and not receiving proactive updates anymore.
SUSE CaaS Platform 4.0 kernel-source Analysis
SUSE Enterprise Storage 6 kernel-source Analysis
SUSE Enterprise Storage 7 kernel-source Analysis
SUSE Enterprise Storage 7.1 kernel-source Analysis
SUSE Linux Enterprise Desktop 11 SP4 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP6 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP1 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP2 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP3 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP4 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP6 kernel-source Analysis
SUSE Linux Enterprise Micro 5.0 kernel-default Analysis
SUSE Linux Enterprise Micro 5.1 kernel-default Analysis
SUSE Linux Enterprise Micro 5.2 kernel-default Analysis
SUSE Linux Enterprise Micro 5.2 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP4 kernel-source-rt Analysis
SUSE Linux Enterprise Real Time 15 SP5 kernel-source-rt Analysis
SUSE Linux Enterprise Server 11 SP4 kernel-source Analysis
SUSE Linux Enterprise Server 11 SP4-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP1-BCL kernel-source Analysis
SUSE Linux Enterprise Server 15 SP1-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP1-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP2-BCL kernel-source Analysis
SUSE Linux Enterprise Server 15 SP2-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP2-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP3-BCL kernel-source Analysis
SUSE Linux Enterprise Server 15 SP3-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP3-LTSS kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP3 kernel-source Analysis
SUSE Manager Proxy 4.0 kernel-source Analysis
SUSE Manager Proxy 4.1 kernel-source Analysis
SUSE Manager Proxy 4.2 kernel-source Analysis
SUSE Manager Retail Branch Server 4.0 kernel-source Analysis
SUSE Manager Retail Branch Server 4.1 kernel-source Analysis
SUSE Manager Retail Branch Server 4.2 kernel-source Analysis
SUSE Manager Server 4.0 kernel-source Analysis
SUSE Manager Server 4.1 kernel-source Analysis
SUSE Manager Server 4.2 kernel-source Analysis
SUSE Real Time Module 15 SP4 kernel-source-rt Analysis
SUSE Real Time Module 15 SP5 kernel-source-rt Analysis
openSUSE Leap 15.3 kernel-source Analysis
openSUSE Leap 15.4 kernel-source Analysis
openSUSE Leap 15.4 kernel-source-rt Analysis
openSUSE Leap 15.5 kernel-source Analysis
openSUSE Leap 15.5 kernel-source-rt Analysis
openSUSE Leap 15.6 kernel-source Analysis


SUSE Timeline for this CVE

CVE page created: Sat Aug 22 21:38:54 2026
CVE page last modified: Sat Aug 22 21:38:54 2026