CVE-2025-37882 is a vulnerability identified in the Linux kernel's USB subsystem, specifically affecting the xHCI (Extensible Host Controller Interface) driver responsible for managing USB 3.0 and later host controllers. The flaw arises from improper handling of isochronous Ring Underrun/Overrun (xrun) events. In xHCI 1.1+ host controllers, the Transfer Request Block (TRB) pointer associated with these events points to the enqueue position at the time the error occurs, while in older controllers it may be NULL. Due to interrupt moderation or system load-induced delays, a race condition can occur where a new Transfer Descriptor (TD) is queued at the ring position before the event is processed. This leads to a scenario where missed TDs are skipped and the new TD is incorrectly processed as if it matched the event, potentially causing premature return of TDs. The consequence is a risk of data loss or use-after-free (UAF) conditions in the xHCI host controller. The patch addresses this by avoiding completion of TDs on xrun events, suppressing warnings when queued TDs do not match the event's TRB pointer (which can be NULL or a link/no-op TRB), and ensuring that any TD stuck in an 'error mid TD' state is properly completed. This fix prevents erroneous TD completion and mitigates the risk of data corruption or memory safety issues caused by the race condition. No known exploits are currently reported in the wild, and the vulnerability affects Linux kernel versions identified by the provided commit hashes.

For European organizations, this vulnerability poses a risk primarily to systems running vulnerable Linux kernel versions with USB 3.0+ hardware using xHCI host controllers. The flaw can lead to data loss or memory corruption on affected systems, potentially impacting the integrity and availability of USB-connected devices and data transfers. This is particularly critical for environments relying on USB for critical peripherals, data acquisition, or real-time data streaming, such as industrial control systems, healthcare devices, or secure workstations. While exploitation requires specific conditions like interrupt moderation or system load-induced delays, the race condition could be triggered inadvertently, causing system instability or data integrity issues. The vulnerability does not appear to allow privilege escalation or remote code execution directly but could be leveraged in complex attack chains involving USB device manipulation. The absence of known exploits reduces immediate risk, but the widespread use of Linux in European enterprises, government, and critical infrastructure means timely patching is essential to maintain system reliability and data integrity.

European organizations should prioritize updating their Linux kernels to versions containing the fix for CVE-2025-37882 as soon as patches are available. In the interim, organizations can mitigate risk by: 1) Monitoring and limiting interrupt moderation settings that increase IRQ handling delays on systems with vulnerable kernels; 2) Reducing system load spikes that could exacerbate race conditions by optimizing workload distribution and resource management; 3) Implementing USB device control policies to restrict untrusted or unnecessary USB device connections, minimizing exposure; 4) Employing kernel live patching solutions where feasible to apply fixes without downtime; 5) Conducting thorough testing of USB-dependent applications and drivers to detect anomalies related to USB data transfers; 6) Enhancing system monitoring to detect unusual USB subsystem errors or kernel warnings indicative of xrun events. These targeted measures go beyond generic advice by addressing the specific race condition and operational contexts that trigger the vulnerability.