CVE-2026-68389 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_qca: Clear memdump state on invalid dump size
qca_controller_memdump() allocates qca->qca_memdump before processing the first dump packet. For a sequence-zero packet it then disables IBS, marks memdump collection active, and reads the advertised dump size.
If the controller reports a zero dump size, the error path frees the local qca_memdump object and returns without clearing qca->qca_memdump or undoing the collection state. A later memdump work item initializes its local pointer from qca->qca_memdump and skips allocation when that pointer is non-NULL, so it can operate on freed memory. The stale collection and IBS-disabled flags can also leave waiters or later transmit handling blocked behind an aborted dump.
Clear the saved pointer and memdump state before returning from the invalid-size path, matching the cleanup used when hci_devcd_init() fails.
A static analysis checker reported the stale memdump state, and manual source review confirmed the invalid-size failure path.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability exists within the Linux kernel's Bluetooth subsystem, specifically in the qca_controller_memdump function of the hci_qca driver which handles Qualcomm Bluetooth controllers. The flaw represents a classic use-after-free condition that occurs when processing memory dump requests from Bluetooth controllers. The vulnerability stems from improper state management during error handling scenarios where the system fails to properly clean up allocated resources and internal flags.
The technical implementation involves a sequence where qca_controller_memdump() first allocates a qca_memdump structure to hold memory dump data before processing the initial dump packet. When the controller reports an invalid zero dump size, the function enters an error path that frees the local qca_memdump object but fails to clear the global qca->qca_memdump pointer or reset the memdump collection state. This creates a dangerous race condition where subsequent memory dump work items attempt to reuse the stale pointer and operate on freed memory.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can lead to system instability, denial of service, and potential privilege escalation scenarios. The failure path leaves IBS (Internal Buffer Status) disabled and collection state active, which can block waiters or interfere with subsequent transmission handling operations. This represents a failure in the principle of proper resource cleanup during error conditions, where the system fails to maintain consistent internal state following abnormal termination paths.
The vulnerability aligns with CWE-415: Double Free and CWE-416: Use After Free categories from the Common Weakness Enumeration framework, demonstrating how improper memory management can create persistent system instability. From an ATT&CK perspective, this weakness could enable privilege escalation or denial of service through persistent system state corruption. The fix implements proper cleanup by clearing the saved pointer and memdump state before returning from the invalid-size error path, ensuring that subsequent operations start with a clean slate matching the cleanup behavior used in other failure scenarios like hci_devcd_init() failures.
This type of vulnerability highlights the critical importance of maintaining consistent internal state management during error handling, particularly in kernel drivers where resource management failures can have system-wide consequences. The static analysis tool detection emphasizes the value of automated code analysis in identifying subtle memory safety issues that might otherwise remain undetected until exploited in production environments.