CVE-2026-98296
Summary
by MITRE • 10/06/2026
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btintel_pcie: validate TX skb length in send_sync
btintel_pcie_prepare_tx() copies skb->len bytes into a fixed BTINTEL_PCIE_BUFFER_SIZE (4096) DMA slot via an unchecked memcpy. Oversized packets are currently rejected only in btintel_pcie_send_frame(); any future caller of btintel_pcie_send_sync() would silently overflow the DMA buffer.
Add the bounds check in btintel_pcie_send_sync() itself, right before skb_push() and the DMA copy.
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Analysis
by VulDB Data Team • 10/06/2026
The Linux kernel Bluetooth subsystem contains a critical memory safety vulnerability within the Intel PCIe driver component, specifically affecting the function btintel_pcie_send_sync. This flaw stems from an insufficient validation of input data lengths prior to performing direct memory operations. The core issue lies in how transmission buffers are handled during synchronous communication with the hardware. When the system prepares to send data via this specific synchronization path, it relies on a fixed-size DMA buffer defined by BTINTEL_PCIE_BUFFER_SIZE, which is set to 4096 bytes. The vulnerability arises because the function btintel_pcie_prepare_tx performs an unchecked memcpy operation that copies skb->len bytes directly into this limited slot without verifying whether the source data exceeds the destination capacity.
This architectural oversight creates a classic buffer overflow scenario where oversized packets can silently corrupt adjacent memory regions in kernel space. While other code paths such as btintel_pcie_send_frame include necessary boundary checks to reject oversized frames, the send_sync function lacks these safeguards. Consequently, any future caller or existing usage of btintel_pcie_send_sync that processes data larger than 4096 bytes will trigger an out-of-bounds write. This type of flaw is categorized under CWE-120 Buffer Copy without Checking Size of Input and represents a significant risk to system stability and security because it allows for potential arbitrary code execution or privilege escalation if the overflowed memory contains critical kernel structures or control flow data.
The operational impact of this vulnerability extends beyond simple application crashes. Because the copy occurs before skb_push, which modifies the socket buffer structure, an oversized write can corrupt not only adjacent DMA buffers but also metadata associated with network packet processing. This corruption can lead to unpredictable system behavior, including kernel panics that result in denial of service for all users on the affected machine. Furthermore, sophisticated attackers could potentially exploit this memory overwrite to bypass security mechanisms or escalate privileges from a user-space process to root-level access within the operating system. The lack of immediate rejection means the error propagates deep into the driver stack before any meaningful validation occurs, increasing the attack surface and difficulty of detection during normal operation.
Mitigation strategies must address both the immediate code defect and broader defensive posture. The primary remediation involves applying the upstream kernel patch that introduces explicit bounds checking within btintel_pcie_send_sync immediately prior to skb_push and the DMA copy operations. This ensures that any packet exceeding 4096 bytes is rejected at the earliest possible point in the processing pipeline, preventing the unsafe memory write entirely. Administrators should prioritize updating their Linux kernels to versions where this fix has been integrated. Additionally, organizations can implement runtime protection mechanisms such as Kernel Address Sanitizer (KASAN) during development and testing phases to detect similar buffer overflows early. Enabling strict access controls on Bluetooth interfaces and monitoring for anomalous memory allocation patterns in production environments further reduces the likelihood of successful exploitation by limiting exposure vectors and enhancing visibility into potential abuse attempts aligned with ATT&CK techniques involving local privilege escalation or defense evasion through kernel manipulation.