CVE-2026-90196 in Linux
Summary
by MITRE • 09/17/2026
In the Linux kernel, the following vulnerability has been resolved:
ASoC: SOF: validate topology volume range before allocation
SOF treats the topology mixer min and max values as non-negative indices into its volume table. It stores them in signed fields, allocates max + 1 entries through an int argument, and later indexes the table with the stored range.
An inverted range is invalid, while a maximum at or above INT_MAX cannot be represented safely after the increment or in the signed fields. Validate the complete range before storing it or allocating the table.
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Analysis
by VulDB Data Team • 09/17/2026
The Linux kernel's Sound Open Firmware subsystem contains a critical logic flaw related to the validation of topology volume ranges during mixer initialization. This vulnerability stems from an insufficient check on user-supplied or firmware-provided configuration data, specifically regarding the minimum and maximum values defined in the audio topology. The SOF driver interprets these min and max parameters as non-negative indices into an internal volume control table. However, the implementation stores these values in signed integer fields without verifying that they form a valid, positive range before proceeding with memory allocation and subsequent indexing operations. This lack of rigorous input validation creates a pathway for potential out-of-bounds access or arithmetic overflow conditions when processing malformed topology files.
The technical core of this flaw lies in how the driver handles the maximum volume value. The code allocates an array of entries based on the formula max plus one, passing this result as an argument to memory allocation functions that expect a signed integer size parameter. If the provided maximum value is at or near INT_MAX, adding one results in a signed integer overflow, wrapping around to a negative number. This can lead to allocating significantly less memory than intended or triggering kernel warnings and potential crashes due to invalid allocation sizes. Furthermore, even if the allocation succeeds, using an inverted range where the minimum value exceeds the maximum value allows for logical errors during index calculations. Since these values are treated as indices later in the execution flow, any inconsistency between min and max can result in accessing memory outside the bounds of the allocated volume table, leading to information disclosure or denial of service conditions depending on the specific memory layout and access patterns.
From a security architecture perspective, this vulnerability aligns with CWE-190 Integer Overflow or Wraparound and CWE-20 Improper Input Validation. The failure to validate that min is less than or equal to max before storage represents a classic boundary condition error common in systems programming where assumptions about data integrity are not enforced at the point of entry. In terms of attack vectors, this could be exploited by an attacker with access to load custom audio topology files into the SOF firmware environment. While direct remote exploitation is unlikely without local file system or device interface privileges, it poses a significant risk for privilege escalation if combined with other vulnerabilities in the kernel's sound subsystem. The ATT&CK framework categorizes such behaviors under techniques involving improper input validation that can lead to memory corruption, potentially facilitating lateral movement within a compromised host by destabilizing critical driver components.
The operational impact of this vulnerability includes potential system instability and crashes when malformed topology data is processed. An attacker could craft a malicious audio configuration file containing extreme values for volume ranges to trigger the integer overflow or invalid index access. This would likely result in a kernel panic, causing a denial of service for all users on the affected machine. In more complex scenarios involving adjacent memory structures, out-of-bounds reads might leak sensitive information from kernel space, while writes could corrupt critical data structures, potentially leading to arbitrary code execution if other mitigations like KASLR or stack canaries are bypassed. The severity is heightened by the fact that audio drivers often run with elevated privileges and handle frequent user interactions through ALSA interfaces.
To mitigate this vulnerability, it is essential to enforce strict validation of topology parameters before any memory allocation occurs. Developers must ensure that both minimum and maximum volume values are non-negative and that the minimum value does not exceed the maximum value. Additionally, checks should be implemented to prevent integer overflow during the calculation of array sizes, such as verifying that max plus one does not wrap around or exceed a safe threshold well below INT_MAX. Applying these validation rules at the earliest point of data ingestion ensures that invalid configurations are rejected early in the initialization process, preventing subsequent arithmetic errors and memory corruption issues. Regular code audits focusing on integer handling and boundary checks in kernel drivers are recommended to prevent similar classes of vulnerabilities from being introduced into the Linux sound subsystem.