CVE-2022-48701 in Linux
Summary
by MITRE • 05/03/2024
In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Fix an out-of-bounds bug in __snd_usb_parse_audio_interface()
There may be a bad USB audio device with a USB ID of (0x04fa, 0x4201) and the number of it's interfaces less than 4, an out-of-bounds read bug occurs when parsing the interface descriptor for this device.
Fix this by checking the number of interfaces.
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Analysis
by VulDB Data Team • 10/02/2025
The vulnerability identified as CVE-2022-48701 represents a critical out-of-bounds read flaw within the Linux kernel's Advanced Linux Sound Architecture subsystem, specifically in the usb-audio driver component. This issue manifests during the parsing of USB audio interface descriptors when processing devices that do not conform to expected USB audio device specifications. The flaw occurs in the __snd_usb_parse_audio_interface() function which is responsible for analyzing and configuring USB audio devices that connect to Linux systems through the USB bus. The vulnerability is particularly concerning because it can be triggered by malformed USB audio devices that present invalid USB interface configurations, making it exploitable through physical device connection rather than network-based attacks.
The technical implementation of this vulnerability stems from insufficient input validation within the USB audio parsing logic. When the kernel encounters a USB audio device with a specific vendor ID 0x04fa and product ID 0x4201, the system attempts to parse interface descriptors without first verifying that the device possesses the expected number of interfaces. The affected device configuration contains fewer than four interfaces, but the parsing function assumes a minimum of four interfaces exist. This assumption leads to memory access violations when the code attempts to read beyond the allocated interface descriptor boundaries, resulting in potential system instability or information disclosure. This type of vulnerability falls under CWE-129, which specifically addresses insufficient bounds checking, and more broadly aligns with CWE-787, concerning out-of-bounds write operations that can lead to memory corruption.
The operational impact of CVE-2022-48701 extends beyond simple system crashes or hangs, as it represents a potential vector for privilege escalation or denial of service attacks in environments where untrusted USB devices are permitted to connect. Attackers could potentially exploit this vulnerability by connecting a malicious USB audio device that presents the specific USB ID 0x04fa:0x4201 with an invalid interface count configuration. The vulnerability affects systems running Linux kernel versions prior to the fix, making it particularly relevant for embedded systems, servers, and desktop environments that support USB audio device connectivity. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.001, which involves command and scripting interpreter usage, and T1566.001, concerning spearphishing attachment, as attackers could potentially leverage USB devices to establish initial access or maintain persistence within targeted environments.
The resolution for CVE-2022-48701 involves implementing proper bounds checking within the USB audio interface parsing logic before attempting to access interface descriptors. The fix requires verifying that the number of available interfaces meets the minimum expected count before proceeding with parsing operations. This defensive programming approach ensures that the kernel's usb-audio subsystem can gracefully handle malformed USB audio devices without attempting to access memory locations outside the valid interface descriptor range. The mitigation strategy essentially implements a precondition check that prevents the out-of-bounds read condition from occurring, thereby protecting the kernel from potential memory corruption or information leakage. System administrators should ensure their Linux systems are updated to kernel versions that include this patch, particularly in environments where USB device management is not strictly controlled. The fix demonstrates proper adherence to secure coding practices that emphasize input validation and bounds checking, which are fundamental requirements for maintaining system integrity and preventing memory safety violations in kernel space operations.