CVE-2022-48926 in Linux
Summary
by MITRE • 08/22/2024
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: rndis: add spinlock for rndis response list
There's no lock for rndis response list. It could cause list corruption if there're two different list_add at the same time like below. It's better to add in rndis_add_response / rndis_free_response / rndis_get_next_response to prevent any race condition on response list.
[ 361.894299] [1: irq/191-dwc3:16979] list_add corruption.
next->prev should be prev (ffffff80651764d0), but was ffffff883dc36f80. (next=ffffff80651764d0).
[ 361.904380] [1: irq/191-dwc3:16979] Call trace:
[ 361.904391] [1: irq/191-dwc3:16979] __list_add_valid+0x74/0x90
[ 361.904401] [1: irq/191-dwc3:16979] rndis_msg_parser+0x168/0x8c0
[ 361.904409] [1: irq/191-dwc3:16979] rndis_command_complete+0x24/0x84
[ 361.904417] [1: irq/191-dwc3:16979] usb_gadget_giveback_request+0x20/0xe4
[ 361.904426] [1: irq/191-dwc3:16979] dwc3_gadget_giveback+0x44/0x60
[ 361.904434] [1: irq/191-dwc3:16979] dwc3_ep0_complete_data+0x1e8/0x3a0
[ 361.904442] [1: irq/191-dwc3:16979] dwc3_ep0_interrupt+0x29c/0x3dc
[ 361.904450] [1: irq/191-dwc3:16979] dwc3_process_event_entry+0x78/0x6cc
[ 361.904457] [1: irq/191-dwc3:16979] dwc3_process_event_buf+0xa0/0x1ec
[ 361.904465] [1: irq/191-dwc3:16979] dwc3_thread_interrupt+0x34/0x5c
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Analysis
by VulDB Data Team • 08/10/2025
The vulnerability described in CVE-2022-48926 represents a critical race condition within the Linux kernel's USB gadget subsystem, specifically affecting the RNDIS (Remote Network Driver Interface Specification) implementation. This flaw manifests as a lack of proper synchronization mechanisms for the RNDIS response list, which is a fundamental data structure used to manage network responses in USB gadget drivers. The absence of appropriate locking primitives creates a scenario where concurrent access to the list can result in severe data corruption, potentially leading to system instability or compromise. The issue was identified through kernel panic traces showing list corruption errors, where the integrity of linked list pointers was violated during simultaneous list_add operations.
The technical root cause of this vulnerability lies in the improper handling of concurrent access to the RNDIS response list structure within the USB gadget framework. When multiple threads or interrupt contexts attempt to modify the response list simultaneously, particularly during the addition or removal of response entries, the absence of spinlock protection allows for race conditions to occur. The kernel's rndis_add_response, rndis_free_response, and rndis_get_next_response functions all operate on this shared data structure without adequate synchronization, creating a classic multi-threading hazard. According to CWE-362, this vulnerability maps directly to a concurrent execution without proper synchronization, while the ATT&CK framework would categorize this under privilege escalation through kernel exploitation techniques.
The operational impact of this vulnerability extends beyond simple system crashes, as it can enable malicious actors to exploit the race condition for more sophisticated attacks. The list corruption detected in the kernel logs demonstrates that the memory management structures have been compromised, potentially allowing for memory corruption that could be leveraged to execute arbitrary code with kernel privileges. This type of vulnerability is particularly dangerous in embedded systems or devices that rely heavily on USB gadget functionality for network operations, as it could enable attackers to gain unauthorized access to the underlying system. The specific error messages indicate that the list_add operation failed because the next pointer's prev field contained an invalid value, suggesting that the corrupted list structure could be manipulated to redirect execution flow or corrupt other kernel data structures.
Mitigation strategies for CVE-2022-48926 require immediate implementation of proper spinlock protection around all operations that modify the RNDIS response list. The fix involves adding spinlock acquisition and release calls within the rndis_add_response, rndis_free_response, and rndis_get_next_response functions to ensure exclusive access to the shared data structure. This approach aligns with standard kernel development practices for protecting shared resources and prevents concurrent access that could lead to memory corruption. System administrators should prioritize updating to kernel versions that include the fix, as the vulnerability affects the core USB gadget functionality and could be exploited in various attack scenarios. Additionally, monitoring for kernel panic messages related to list corruption should be implemented as part of security operations to detect potential exploitation attempts. The solution represents a fundamental defensive measure against race condition vulnerabilities in kernel-level USB subsystems, emphasizing the importance of proper synchronization mechanisms in multi-threaded environments.