CVE-2024-56590 in Linux
Summary
by MITRE • 12/27/2024
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_core: Fix not checking skb length on hci_acldata_packet
This fixes not checking if skb really contains an ACL header otherwise the code may attempt to access some uninitilized/invalid memory past the valid skb->data.
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Analysis
by VulDB Data Team • 01/05/2026
The vulnerability CVE-2024-56590 represents a critical memory safety issue within the Linux kernel's Bluetooth subsystem, specifically in the hci_core module responsible for handling Bluetooth HCI (Host Controller Interface) communications. This flaw exists in the processing of ACL (Asynchronous Connection-Less) data packets, which are fundamental to Bluetooth data transmission between devices. The vulnerability stems from inadequate input validation during packet processing, creating a potential pathway for memory corruption that could be exploited by malicious actors.
The technical root cause of this vulnerability lies in the failure to validate the length of socket buffer (skb) structures before attempting to access ACL headers within the Bluetooth HCI core implementation. When the kernel receives Bluetooth ACL data packets, it processes them through the hci_acldata_packet function without first ensuring that the incoming data contains sufficient bytes to constitute a valid ACL header. This oversight allows the code to potentially access memory locations beyond the legitimate skb->data boundaries, leading to uninitialized memory access patterns that can result in unpredictable behavior including kernel crashes, memory corruption, or potential privilege escalation.
From an operational perspective, this vulnerability poses significant risks to systems running Linux kernels with Bluetooth capabilities, particularly those that process untrusted Bluetooth data from external devices. The impact extends across various device types including smartphones, laptops, IoT devices, and embedded systems that rely on Bluetooth connectivity. Attackers could potentially exploit this weakness by crafting specially malformed Bluetooth ACL packets that trigger the memory access violation, potentially leading to denial of service conditions or in more sophisticated scenarios, arbitrary code execution within kernel space. The vulnerability's classification aligns with CWE-129, which addresses insufficient validation of length of input buffers, and represents a classic example of buffer over-read conditions that can compromise system integrity.
The exploitation of this vulnerability requires an attacker to be within range of a target device and capable of transmitting malicious Bluetooth packets to the system. This makes it particularly concerning for IoT deployments and mobile devices where Bluetooth is frequently enabled and exposed to untrusted networks. Mitigation strategies should focus on applying the kernel patches that implement proper skb length validation before ACL header processing, ensuring that all incoming Bluetooth data packets meet minimum size requirements before any header parsing occurs. System administrators should prioritize updating kernel versions to include the patched hci_core implementation, while network security teams should consider implementing Bluetooth traffic monitoring to detect anomalous packet patterns that might indicate exploitation attempts. The vulnerability's resolution through proper input validation demonstrates the critical importance of defensive programming practices in kernel-level code, aligning with ATT&CK technique T1068 which addresses exploit for privilege escalation through kernel vulnerabilities.