Bug 2562765 (CVE-2026-99182)

Summary: CVE-2026-99182 kernel: ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Sound Open Firmware (SOF) audio subsystem. When handling aggregated audio capture configurations where the channel count is smaller than the number of aggregated devices, an integer underflow occurs in the IPC4 topology driver. A local user could trigger this condition by configuring a specific audio stream, causing an out-of-bounds bit shift that leads to a kernel crash and a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-10-28 11:05:48 UTC 
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.
Comment 1 gkamathe 2026-10-29 06:04:12 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-99182.mbox