CVE-2026-23164 in Linux
Summary
by MITRE • 02/14/2026
In the Linux kernel, the following vulnerability has been resolved:
rocker: fix memory leak in rocker_world_port_post_fini()
In rocker_world_port_pre_init(), rocker_port->wpriv is allocated with kzalloc(wops->port_priv_size, GFP_KERNEL). However, in rocker_world_port_post_fini(), the memory is only freed when wops->port_post_fini callback is set:
if (!wops->port_post_fini) return; wops->port_post_fini(rocker_port); kfree(rocker_port->wpriv);
Since rocker_ofdpa_ops does not implement port_post_fini callback (it is NULL), the wpriv memory allocated for each port is never freed when ports are removed. This leads to a memory leak of sizeof(struct ofdpa_port) bytes per port on every device removal.
Fix this by always calling kfree(rocker_port->wpriv) regardless of whether the port_post_fini callback exists.
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Analysis
by VulDB Data Team • 05/05/2026
The vulnerability described in CVE-2026-23164 represents a critical memory management flaw within the Linux kernel's rocker network driver implementation. This issue specifically affects the rocker driver's handling of port-specific private data structures during device lifecycle operations. The flaw resides in the rocker_world_port_post_fini() function where memory allocated during port initialization is not consistently freed, creating a persistent memory leak pattern that accumulates over time.
The technical root cause stems from an asymmetric memory management approach within the rocker driver's port lifecycle handling. During the rocker_world_port_pre_init() function, the driver allocates memory for port-specific private data structures using kzalloc with the size determined by wops->port_priv_size parameter. This allocation occurs with GFP_KERNEL flags, indicating kernel-level memory allocation that should be properly managed throughout the driver's operational lifecycle. However, the cleanup function rocker_world_port_post_fini() implements conditional memory deallocation logic that depends entirely on the presence of a valid port_post_fini callback function pointer.
The vulnerability manifests when the rocker_ofdpa_ops structure, which defines the operational parameters for OFDPA (OpenFlow Data Plane Abstraction) ports, fails to implement the port_post_fini callback function. This NULL callback condition causes the memory deallocation path to be bypassed entirely, leaving the allocated rocker_port->wpriv memory untouched and unrecoverable. The specific structure size involved is sizeof(struct ofdpa_port) bytes per port, meaning that every time a port is removed from the device, this memory block remains allocated in kernel space, creating a persistent leak that grows with device usage and port management operations.
This memory leak vulnerability directly impacts system stability and resource utilization, particularly in environments where network devices are frequently added and removed or where the rocker driver manages numerous ports simultaneously. The cumulative effect of these leaks can lead to memory exhaustion over extended periods of operation, potentially causing system performance degradation, unexpected reboots, or even denial of service conditions. The issue aligns with CWE-401: "Improper Release of Memory" which categorizes failures to properly release allocated memory resources as a fundamental memory management error. From an operational security perspective, this vulnerability represents a persistent resource consumption issue that could be exploited by attackers to cause resource exhaustion attacks against systems running affected kernel versions.
The fix implemented addresses this flaw by modifying the rocker_world_port_post_fini() function to always execute the kfree(rocker_port->wpriv) operation regardless of whether the port_post_fini callback exists. This ensures that allocated memory is consistently freed during port cleanup operations, preventing the accumulation of memory leaks. The solution follows established security practices for memory management within kernel space, ensuring that all allocated resources are properly released during normal operation and error conditions. This approach aligns with the ATT&CK framework's resource exhaustion tactics, specifically targeting the prevention of persistent memory leaks that could be leveraged to degrade system performance or availability. The fix maintains backward compatibility while ensuring proper resource management across all driver operation paths, eliminating the conditional logic that previously allowed memory to remain allocated indefinitely.