CVE-2026-12999 in Zephyr
Summary
by MITRE • 08/23/2026
The Infineon Airoc Wi-Fi driver's transmit callback airoc_mgmt_send() in drivers/wifi/infineon/airoc_wifi.c allocates a net_buf from the fixed airoc_pool for every outbound packet. When whd_network_send_ethernet_data() returns a synchronous failure, the underlying WHD library does not take ownership of the buffer, but the pre-fix driver returned -EIO without releasing it. Each failed transmit therefore permanently leaks one buffer from the pool.
airoc_pool is small and fixed (AIROC_WIFI_TX_PACKET_POOL_COUNT + AIROC_WIFI_RX_PACKET_POOL_COUNT, default 20 buffers) and is shared by WHD's whd_host_buffer_get callback for both transmit and receive. Once enough send failures have leaked the pool dry, airoc_wifi_host_buffer_get() returns WHD_BUFFER_ALLOC_FAIL for all subsequent allocations, so both transmit and the WHD-driven receive path fail and Wi-Fi connectivity is lost until the device is rebooted.
The leak occurs only on the transmit error path. A Wi-Fi-adjacent attacker can influence the conditions that cause synchronous send failures (for example by deauthenticating/disassociating the station while the local stack continues to attempt transmits), and ordinary transient failures over the device's lifetime accumulate toward the same state. Reliable on-demand triggering is of high complexity and the impact is availability-only, but the resulting denial of service is permanent and non-recoverable without a reboot.
The fix releases the buffer with airoc_wifi_buffer_release() on the failure branch, returning it to the pool. The commit also removes a redundant k_sem_give() in airoc_mgmt_disconnect(); because data->sema_common is a binary semaphore (limit 1) the duplicate give merely saturated at 1 and had no security impact.
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Analysis
by VulDB Data Team • 08/23/2026
The vulnerability identified within the Infineon Airoc Wi-Fi driver represents a critical resource management flaw located in the transmit callback function, specifically airoc_mgmt_send(). This function is responsible for handling outbound network packets by allocating buffers from a fixed-size memory pool known as airoc_pool. The core technical defect arises when the underlying WHD library function whd_network_send_ethernet_data() returns a synchronous failure code. In such scenarios, the WHD library does not assume ownership of the allocated net_buf buffer. However, the pre-fix implementation of the driver incorrectly proceeds to return an -EIO error code without releasing the previously allocated buffer back to the pool. This oversight results in a permanent memory leak for every single transmit operation that encounters this specific failure condition.
The operational impact of this vulnerability is severe due to the constrained nature of the resource being leaked. The airoc_pool is small and fixed, with a default size comprising only twenty buffers shared between transmission and reception paths via the WHD host buffer callback mechanism. As failed transmissions accumulate over time, these unreleased buffers are permanently removed from the available pool. Once the pool is exhausted, subsequent attempts to allocate memory for either new transmit packets or incoming receive data fail, triggering a WHD_BUFFER_ALLOC_FAIL state. This leads to a complete loss of Wi-Fi connectivity on the affected device. Unlike transient network issues, this denial of service is persistent and non-recoverable through normal software recovery mechanisms; it requires a full system reboot to restore functionality by resetting the memory pool allocation counters.
From an attacker perspective, while reliable on-demand triggering may present high complexity due to the need for specific failure conditions, the vulnerability remains exploitable in scenarios where network instability or malicious interference causes synchronous send failures. For instance, an adversary could deauthenticate or disassociate a station from the access point while the local stack continues attempting transmissions, thereby accelerating the exhaustion of the buffer pool. This aligns with CWE-401, which describes missing release of memory after effective usage, and falls under the ATT&CK technique T1499, specifically Endpoint Denial of Service via resource exhaustion. The impact is strictly availability-focused but carries significant operational risk as it renders network-dependent devices inoperable until manual intervention occurs.
The remediation for this issue involves modifying the error handling path within airoc_mgmt_send() to explicitly release the buffer using airoc_wifi_buffer_release() when a transmission failure is detected, thereby returning the resource to the pool and preventing leakage. Additionally, the fix addresses a secondary code quality issue by removing a redundant k_sem_give() call in the airoc_mgmt_disconnect function. Since data->sema_common operates as a binary semaphore with a limit of one, duplicate signaling merely saturates the semaphore at its maximum value without providing any functional benefit or security improvement. This cleanup ensures cleaner synchronization logic but does not directly mitigate the primary memory leak vulnerability.