---
id: "CVE-2026-99182"
kind: "vulnerability"
aliases: ["CVE-2026-99182"]
title: "Linux kernel: SOF audio topology shift error on aggregated mono capture"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "linux-kernel", "sof-audio", "soundwire"]
not_affected_if: ["no-sof-audio-hardware"]
published_at: "2026-10-28T11:17:39+00:00"
first_seen_at: "2026-10-28T11:32:36+00:00"
updated_at: "2026-10-28T11:35:23+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99182", "first_seen_at": "2026-10-28T11:32:36+00:00"}]
---

# Linux kernel: SOF audio topology shift error on aggregated mono capture

In the Linux kernel's SOF audio topology code, a mono capture stream aggregated across multiple SoundWire links causes an out-of-bounds shift, which UBSAN reports. The sources describe a kernel undefined-behaviour bug and do not state an attacker outcome.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- Update to a Linux kernel release that includes the upstream commit 'ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture'
- unknown

## Timeline

- 2026-10-28T11:32:36+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-99182

## From the sources

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

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

When ch_count is smaller than blob->alh_cfg.device_count (e.g. a mono
capture stream, such as a SmartMic, aggregated across multiple SDW
links), step = ch_count / blob->alh_cfg.device_count truncates to 0.
The subsequent GENMASK(step - 1, 0) then underflows step - 1 (u32) to
UINT_MAX, 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 ch_count < device_count the same way as the existing "channels
equal to output reference channels" case: apply the same ch_mask to
every aggregated device instead of trying to split channels that
can't be evenly divided.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_