CVE-2024-35933 in Linux
Summary
by MITRE • 05/19/2024
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btintel: Fix null ptr deref in btintel_read_version
If hci_cmd_sync_complete() is triggered and skb is NULL, then hdev->req_skb is NULL, which will cause this issue.
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Analysis
by VulDB Data Team • 05/27/2025
The vulnerability identified as CVE-2024-35933 represents a critical null pointer dereference flaw within the Linux kernel's Bluetooth subsystem, specifically affecting the btintel driver component. This issue occurs during the execution of the btintel_read_version function, which is responsible for reading version information from Intel Bluetooth hardware components. The flaw manifests when the hci_cmd_sync_complete() callback function is invoked, but the associated socket buffer (skb) parameter becomes NULL, leading to a cascade of null pointer dereferences that can compromise system stability and potentially provide attack vectors for malicious actors.
The technical root cause of this vulnerability stems from inadequate null pointer validation within the Bluetooth Intel driver's command processing logic. When the hci_cmd_sync_complete() function executes, it expects a valid socket buffer to be present in the request structure, but under certain error conditions or timing scenarios, the skb parameter may be NULL. This NULL value propagates through the system, causing hdev->req_skb to also become NULL, resulting in a direct null pointer dereference when subsequent code attempts to access the dereferenced pointer. This type of vulnerability falls under the CWE-476 category of Null Pointer Dereference, which represents one of the most common and dangerous classes of software defects in kernel space programming.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling denial of service conditions that can render Bluetooth functionality completely unavailable on affected systems. In environments where Bluetooth connectivity is critical for device operation, such as automotive systems, industrial control equipment, or mobile devices, this flaw could result in complete service interruption. Additionally, the vulnerability may provide opportunities for privilege escalation attacks, as attackers could potentially exploit the null pointer dereference to manipulate kernel memory structures or gain unauthorized access to system resources. The ATT&CK framework categorizes this type of vulnerability under T1068 - Exploitation for Privilege Escalation and T1499 - Endpoint Termination, as it can be leveraged to compromise system integrity and availability.
Mitigation strategies for CVE-2024-35933 should prioritize immediate patch deployment from kernel maintainers, as the vulnerability affects the core Bluetooth subsystem functionality. System administrators should ensure all Linux distributions are updated to versions containing the fix, which typically involves adding proper null pointer checks before dereferencing the skb parameter in the btintel_read_version function. Additional defensive measures include implementing kernel module hardening techniques such as kernel address space layout randomization and stack canaries to complicate exploitation attempts. Network administrators should monitor for unusual Bluetooth connectivity patterns or system crashes that might indicate exploitation attempts, while also considering temporary Bluetooth interface disabling for systems where wireless connectivity is not immediately required. Organizations should also review their patch management procedures to ensure rapid deployment of security updates across all affected kernel versions and hardware configurations.