CVE-2026-99182: ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

Q: Which systems are exposed to this issue?

Systems using the Linux kernel's ASoC SOF IPC4 topology handling for aggregated ALH capture are affected when the capture channel count is lower than the configured ALH device count. The described example is a mono SmartMic capture stream aggregated across multiple SoundWire links.

Q: What condition triggers the out-of-bounds shift?

The issue occurs when ch_count is smaller than blob->alh_cfg.device_count. Integer division then produces a step value of zero, and constructing GENMASK(step - 1, 0) underflows the unsigned value and causes an invalid shift exponent.

Published Oct 28, 2026

Updated

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

ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

When chcount is smaller than blob->alhcfg.devicecount (e.g. a mono capture stream, such as a SmartMic, aggregated across multiple SDW links), step = chcount / blob->alhcfg.devicecount truncates to 0. The subsequent GENMASK(step - 1, 0) then underflows step - 1 (u32) to UINTMAX, causing GENMASK()'s internal shift to use an out-of-bounds exponent:

UBSAN: shift-out-of-bounds in sound/soc/sof/ipc4-topology.c:2363:13 shift exponent 18446744069414584384 is too large for 64-bit type 'long unsigned int'

Treat chcount < devicecount the same way as the existing "channels equal to output reference channels" case: apply the same chmask to every aggregated device instead of trying to split channels that can't be evenly divided.

Affected Software

1 affected component

Linux Linux kernel

Event History

Oct 28, 2026

CVE Published

via MITRE·10:35 AM

Data Sourced

via MITRE·10:35 AM

Description

Frequently Asked Questions

Which systems are exposed to this issue?

Systems using the Linux kernel's ASoC SOF IPC4 topology handling for aggregated ALH capture are affected when the capture channel count is lower than the configured ALH device count. The described example is a mono SmartMic capture stream aggregated across multiple SoundWire links.

What condition triggers the out-of-bounds shift?

The issue occurs when ch_count is smaller than blob->alh_cfg.device_count. Integer division then produces a step value of zero, and constructing GENMASK(step - 1, 0) underflows the unsigned value and causes an invalid shift exponent.

How does the fix change handling of these capture configurations?

For channel counts below the device count, the fix treats the configuration like the existing case where channels equal the output reference channels. It applies the same channel mask to every aggregated device rather than attempting to split channels among devices.

CVE-2026-99182: ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

Affected Software

Event History

Frequently Asked Questions

Which systems are exposed to this issue?

What condition triggers the out-of-bounds shift?

How does the fix change handling of these capture configurations?

Company

Resources

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Frequently Asked Questions

Which systems are exposed to this issue?

What condition triggers the out-of-bounds shift?

How does the fix change handling of these capture configurations?