CVE-2025-37813 is a vulnerability identified in the Linux kernel's USB xHCI (Extensible Host Controller Interface) driver, specifically related to a workaround for Etron USB host controllers. The flaw arises from an invalid pointer dereference during the handling of transfer ring buffers (TRBs) in the USB host controller driver code. The vulnerability occurs because the code performs a pointer dereference on 'enqueue + 1' without verifying its validity, which can lead to either a kernel crash (due to dereferencing an invalid pointer) or corruption of the transfer ring buffer by replacing a legitimate link TRB with a NOOP. This bug manifests sporadically, approximately 0.4% of the time the affected code path is executed, and has been confirmed to cause system crashes during control transfer stress tests on Etron host controllers. The root cause is a logic error in the pointer validation check before the functions prepare_transfer() and prepare_ring() are called. The fix involves replacing the faulty pointer dereference with a functionally equivalent test that does not dereference the pointer and reliably determines the correct condition, preventing invalid memory access and ensuring kernel stability. This vulnerability affects multiple Linux kernel versions identified by specific commit hashes, indicating it is present in recent kernel releases prior to the patch. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a risk primarily to systems running Linux kernels that include the affected xHCI USB driver code, especially those using Etron USB host controllers. The impact includes potential denial of service due to kernel crashes, which can disrupt critical services, cause system instability, and lead to data loss or corruption if crashes occur during active USB data transfers. While this vulnerability does not directly allow privilege escalation or remote code execution, the resulting instability could be exploited in multi-stage attacks or cause operational disruptions in environments relying on USB devices for security tokens, storage, or peripherals. Industries with high reliance on Linux-based infrastructure, such as telecommunications, finance, manufacturing, and public sector entities in Europe, could experience operational downtime. The lack of known exploits reduces immediate risk, but the vulnerability’s presence in widely used Linux kernels means that unpatched systems remain vulnerable to accidental crashes or targeted stress testing attacks. Given the kernel-level nature of the flaw, recovery from crashes may require system reboots, impacting availability and potentially leading to cascading failures in clustered or virtualized environments.

European organizations should prioritize applying the official Linux kernel patches that address CVE-2025-37813 as soon as they become available from their Linux distribution vendors. Since the vulnerability is tied to specific kernel commits, verifying kernel versions and applying updates or backported patches is critical. Organizations using Etron USB host controllers should conduct targeted testing to confirm the presence of the vulnerability and validate patch effectiveness. Additionally, system administrators should monitor kernel logs for signs of USB-related crashes or anomalies and consider temporarily disabling or limiting the use of Etron USB host controllers in critical systems until patches are applied. Implementing kernel crash dump analysis can help diagnose and respond to incidents caused by this flaw. For environments where patching is delayed, isolating affected systems from critical networks or reducing USB device usage can mitigate impact. Finally, maintaining robust backup and recovery procedures will minimize data loss risks from unexpected system crashes.