CVE-2026-23334 in Linux
Summary
by MITRE • 03/25/2026
In the Linux kernel, the following vulnerability has been resolved:
can: usb: f81604: handle short interrupt urb messages properly
If an interrupt urb is received that is not the correct length, properly detect it and don't attempt to treat the data as valid.
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Analysis
by VulDB Data Team • 03/30/2026
The vulnerability identified as CVE-2026-23334 resides within the Linux kernel's CAN (Controller Area Network) USB driver implementation, specifically affecting the f81604 USB controller support. This issue represents a classic buffer over-read condition that occurs when processing interrupt urb messages, demonstrating a fundamental flaw in input validation and data handling procedures. The vulnerability affects systems utilizing USB-based CAN interfaces, particularly those employing the f81604 controller chip, which is commonly found in automotive diagnostic tools, industrial automation equipment, and embedded communication systems where reliable network communication is critical.
The technical flaw manifests when the USB driver receives an interrupt urb message that does not conform to the expected data structure or length requirements. In normal operation, the driver expects interrupt urb messages to contain specific amounts of data that match predefined protocols and formats. However, when an unexpected message length is received, the driver fails to properly validate the message boundaries before attempting to process the data. This inadequate validation creates a scenario where the driver may attempt to read beyond the allocated memory boundaries, treating invalid or truncated data as legitimate information. The vulnerability stems from a lack of proper bounds checking and input sanitization within the USB interrupt handling routine, which directly violates secure coding practices and can lead to unpredictable behavior or system instability.
The operational impact of this vulnerability extends beyond simple system crashes or hangs, potentially enabling more serious security consequences within embedded and automotive systems that rely on CAN communication protocols. When an attacker can manipulate the USB interface to send malformed interrupt urb messages, they may be able to trigger memory corruption that could lead to privilege escalation, denial of service conditions, or even code execution in certain scenarios. The vulnerability particularly affects automotive systems where CAN buses are used for critical vehicle functions such as brake control, steering systems, or engine management, making this a potentially serious concern for automotive cybersecurity. Systems utilizing USB CAN adapters for diagnostics, testing, or communication purposes are at risk, especially when these devices are connected to untrusted networks or environments where malicious input could be injected.
Mitigation strategies for this vulnerability require immediate kernel updates and patches from Linux kernel maintainers, as the fix must address the core validation logic within the f81604 USB driver implementation. System administrators should prioritize applying the latest kernel security patches that include proper bounds checking for interrupt urb message lengths, ensuring that all USB CAN interfaces are protected against malformed data processing. Additionally, network segmentation and access controls should be implemented to limit exposure of USB CAN interfaces to untrusted systems, particularly in automotive and industrial environments where such interfaces may be connected to critical infrastructure. Organizations should also consider implementing monitoring solutions that can detect anomalous USB communication patterns and provide early warning of potential exploitation attempts, aligning with the principle of defense in depth as outlined in cybersecurity frameworks such as the NIST Cybersecurity Framework and ISO 27001 standards. The vulnerability demonstrates the importance of robust input validation and proper error handling in embedded systems, as highlighted by CWE-129 and CWE-131 categories related to improper input validation and insufficient boundary checks.