CVE-2026-98732 in Linux
Summary
by MITRE • 10/18/2026
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btintel: fix buffer over-read in btintel_hw_error()
The "Exception info %s" print uses skb->data + 1, but the 12-byte payload is not guaranteed to be NUL-terminated and can be read past its end.
Bound the print with "%.*s" and skb->len - 1.
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Analysis
by VulDB Data Team • 10/18/2026
The Linux kernel Bluetooth subsystem contains a specific vulnerability within the Intel wireless driver component, identified by the function btintel_hw_error(). This issue manifests as an out-of-bounds read error when processing hardware exception information reported during device operation. The root cause lies in how string data is extracted from network buffers for logging purposes. Specifically, the code attempts to print an Exception info field using a standard format specifier that expects a null-terminated C-string. However, the underlying payload retrieved from the socket buffer has a fixed length of twelve bytes and does not guarantee termination with a zero byte at its end. Consequently, when the printing routine traverses this memory region looking for the terminator, it reads beyond the allocated boundary into adjacent kernel memory spaces.
This type of vulnerability is classified under CWE-126, which denotes Buffer Over-read. In terms of attack surface and tactical classification, this aligns with ATT&CK technique T1083, specifically related to File and Directory Discovery or potentially data exfiltration if the leaked information reveals sensitive kernel state details. While immediate exploitation for arbitrary code execution is unlikely due to the read-only nature of the flaw, such memory leaks can provide attackers with valuable intelligence about internal kernel structures, loaded modules, or other security-sensitive data residing in adjacent memory pages. This undermines the confidentiality guarantees expected from secure system operation and violates fundamental principles of safe memory access patterns mandated by modern operating system design standards.
The operational impact of this vulnerability is primarily centered on information disclosure rather than direct privilege escalation or denial of service through crashes, although repeated triggering could theoretically contribute to resource exhaustion if log buffers are filled with malformed output attempts. The severity depends heavily on the context in which the Intel Bluetooth hardware operates and whether an unprivileged user can trigger these hardware error conditions frequently enough to exploit the memory leak effectively. In most standard configurations, this represents a medium-severity issue that requires local physical access or specific driver interaction scenarios to be triggered, but it remains a significant defect in input validation logic within the kernel space.
To mitigate this vulnerability, developers have implemented a corrective patch that modifies the string formatting approach used in btintel_hw_error(). Instead of relying on automatic null-termination detection via standard format specifiers like %s, the fix employs the precision modifier %.*s combined with an explicit length calculation derived from skb->len minus one. This ensures that only the valid bytes within the twelve-byte payload are processed and printed, strictly bounding the read operation to safe limits regardless of whether a terminator exists in memory. This change enforces strict adherence to buffer boundaries and eliminates the possibility of reading uninitialized or unrelated kernel memory during error reporting sequences.
Administrators managing systems with affected Intel Bluetooth drivers should ensure that their kernels are updated to include this patch as soon as possible. Since this is a core driver fix, it typically requires a full system reboot after applying the update to load the corrected module binaries. Additionally, organizations should review their logging configurations to monitor for any unusual patterns of hardware error reports from Bluetooth devices, which might indicate attempted exploitation or abnormal device behavior that could be leveraged in conjunction with other vulnerabilities. Maintaining up-to-date kernel versions remains the most effective defense against such low-level memory safety issues inherent in complex driver implementations.