CVE-2026-43373

Vulnerability

Overview

A memory leak vulnerability exists in the Linux kernel's NCSI (Network Controller Sideband Interface) subsystem. The issue is found in two functions: ncsi_aen_handler() and ncsi_rcv_rsp(). In ncsi_aen_handler(), when an invalid AEN (Asynchronous Event Notification) packet is received, the function returns early without freeing the associated socket buffer (skb). Similarly, in ncsi_rcv_rsp(), early exit paths that occur when the NCSI device, response handler, or request cannot be resolved also fail to release the skb, leading to a memory leak [1].

Exploitation and

Impact

An attacker with the ability to send crafted NCSI packets to a vulnerable system could trigger these early return paths repeatedly. This would cause the kernel to leak memory each time, potentially leading to resource exhaustion over time. No authentication is required for this attack, as NCSI packets are typically received over the network. The vulnerability has a CVSS v3 score of 7.5 (High), indicating significant availability impact [1].

Mitigation

The fix is included in the Linux kernel stable tree as commit 81d6aee32f8f7bbc175c05dbf61f4430bfb88c4a. System administrators should apply the latest kernel updates from their distribution to remediate this issue. No workarounds are mentioned in the advisory [1].