CVE-2026-80900 in Linux
Summary
by MITRE • 09/04/2026
In the Linux kernel, the following vulnerability has been resolved:
ASoC: SDCA: Make UMP message size check more robust
If message offset was larger than the buffer length the size check will pass incorrectly. Refactor the check such that it is more robust to invalid sizes.
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Analysis
by VulDB Data Team • 09/04/2026
The Linux kernel's Advanced System Control Architecture for Audio, commonly referred to as ASoC SDCA, manages communication between audio drivers and hardware components using a structured message protocol. This subsystem relies on precise boundary checks to ensure that data buffers are accessed safely without exceeding their allocated memory limits. The identified vulnerability stems from an insufficient validation mechanism within the UMP (Unified Message Protocol) handler, specifically concerning how message offsets and buffer lengths are compared during runtime operations.
The core technical flaw lies in a logic error where the size check fails to correctly account for scenarios where the message offset exceeds the total buffer length. In standard memory access patterns, if an offset is greater than or equal to the buffer size, any subsequent read or write operation would result in accessing memory outside the intended allocation boundaries. However, due to the flawed comparison logic, this condition was not properly detected as invalid. Consequently, the system proceeded with operations that assumed valid data structures were present, even when the underlying parameters indicated a clear violation of memory safety constraints.
This vulnerability creates a significant risk for out-of-bounds reads or writes, which are classified under CWE-125 (Out-of-bounds Read) and CWE-787 (Out-of-bounds Write). An attacker who can influence the message offset parameter could potentially exploit this weakness to read sensitive kernel memory contents that lie beyond the buffer's end. Alternatively, if write operations are permitted in similar contexts, it could lead to heap corruption or arbitrary code execution by overwriting adjacent memory structures. The impact is particularly severe because ASoC SDCA operates at a low level within the audio subsystem, which often has elevated privileges and direct access to hardware resources.
From an offensive security perspective, this flaw aligns with techniques found in the MITRE ATT&CK framework related to invalid resource manipulation or improper input validation that leads to memory corruption. It represents a classic example of how subtle arithmetic errors in boundary checks can undermine system integrity. The vulnerability highlights the importance of rigorous static analysis and formal verification methods when dealing with low-level kernel interfaces where manual review might miss edge cases involving offset calculations.
To mitigate this risk, the Linux kernel maintainers have refactored the size check logic to ensure it robustly handles invalid sizes. The updated implementation now correctly validates that the message offset does not exceed the buffer length before proceeding with any data processing. This change ensures that out-of-bounds access attempts are rejected early in the execution flow, preventing potential exploitation. System administrators should apply the latest kernel updates containing this patch to close the security gap and maintain the integrity of their audio subsystems against potential memory corruption attacks.