CVE-2026-98293 in Linux
Summary
by MITRE • 10/06/2026
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: ISO: Fix parent socket leak in iso_conn_ready()
iso_get_sock() returns the parent socket with a reference held, which is dropped by sock_put() once the child socket has been set up. The error path taken when iso_sock_alloc() fails only calls release_sock() and returns, leaking the reference and thus the parent socket itself.
Drop the reference on that path as well.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/06/2026
The Linux kernel Bluetooth subsystem contains a resource management flaw within the Isochronous Sockets implementation, specifically in the iso_conn_ready function. This vulnerability arises from an imbalance in reference counting for socket objects during connection establishment procedures. When establishing an ISO connection, the system invokes iso_get_sock to retrieve the parent socket associated with the new connection. This operation correctly increments a reference count on the parent socket to ensure it remains valid while operations are performed on its behalf. Under normal execution paths where subsequent allocation steps succeed, such as when creating child sockets via sock_alloc or similar mechanisms, this extra reference is properly released using sock_put once the setup is complete and the relationship between parent and child is established. However, a critical error handling path fails to mirror this cleanup logic.
The specific technical flaw occurs in scenarios where iso_sock_alloc fails due to resource exhaustion or other allocation errors. In these failure cases, the code execution diverts to an error handler that releases the lock on the socket using release_sock but neglects to call sock_put to decrement the reference count acquired earlier by iso_get_sock. Because Linux kernel objects rely heavily on reference counting for memory management and lifecycle control, failing to drop this reference results in a persistent leak of the parent socket object. This is not merely a minor inefficiency; it represents a classic resource leak vulnerability where system resources are consumed but never returned to the pool for reuse by other processes or subsystems.
From an industry standard perspective, this issue aligns with CWE-401, which describes missing release of memory after effective usage. The failure to properly manage object lifecycles in kernel space can lead to progressive degradation of system stability. Over time, repeated occurrences of this leak will consume available socket structures and associated kernel memory. In the context of ATT&CK techniques related to resource hijacking or denial of service through exhaustion, while this specific bug may not be immediately exploitable for remote code execution, it contributes to a state where the Bluetooth subsystem becomes unresponsive due to lack of available resources. An attacker who can trigger repeated connection attempts that fail at the allocation stage could potentially accelerate this depletion process.
The operational impact of this vulnerability is primarily centered on resource exhaustion and potential denial of service conditions within the local system or network stack. As more parent sockets are leaked, the kernel's ability to allocate new socket structures diminishes. This can lead to increased latency in Bluetooth operations, failure to establish new connections even when resources should theoretically be available due to fragmentation or limits being reached prematurely, and ultimately a crash of the networking subsystem if memory pressure becomes critical. For systems relying heavily on continuous Bluetooth connectivity for IoT devices, audio streaming, or peripheral management, this instability can disrupt services that depend on reliable socket availability.
Mitigation strategies involve applying vendor-provided kernel patches that correct the reference counting logic in iso_conn_ready. Administrators should ensure their Linux distributions are updated to versions containing fixes from upstream kernel maintainers who have addressed this specific leak by adding the necessary sock_put call in the error path of iso_sock_alloc failure handling. Until such updates are applied, monitoring system logs for Bluetooth-related errors and tracking socket usage statistics can help identify systems experiencing abnormal resource consumption patterns associated with this flaw.