CVE-2026-23258: 
Linux Kernel vulnerability analysis and mitigation

CVE-2026-23258 is a memory leak vulnerability in the Linux kernel's liquidio network driver, specifically in the setup_nic_devices() function. The flaw arises because the netdev pointer (oct->props[i].netdev) is not initialized before calls to netif_set_real_num_rx_queues() and netif_set_real_num_tx_queues(); if either call fails, the allocated netdev structure is never freed. The vulnerability affects Linux kernel versions from 4.18 up to (but not including) the fixed stable releases, and was disclosed on March 18, 2026. It carries a CVSS v3.1 base score of 5.5 (Medium) (Red Hat Advisory, Feedly).

The root cause is classified as CWE-401 (Missing Release of Memory after Effective Lifetime). In setup_nic_devices(), alloc_etherdev_mq() allocates a netdev structure, but the pointer is only stored in oct->props[i].netdev after the queue setup functions succeed. If netif_set_real_num_rx_queues() or netif_set_real_num_tx_queues() returns an error, the function exits early and the cleanup routine liquidio_destroy_nic_device() cannot locate the allocated netdev (since the pointer is still NULL), resulting in a kernel memory leak. The issue was discovered via static analysis tooling and code review, and is compile-tested only — no dynamic exploitation has been demonstrated (Red Hat Advisory, Feedly).

Successful exploitation allows a local attacker with low privileges to repeatedly trigger NIC device setup failures, causing the kernel to leak memory on each failed attempt. Over time, this can exhaust available kernel memory and result in a system crash or denial of service. There is no confidentiality or integrity impact; the vulnerability is limited to availability (Red Hat Advisory, Feedly).

Apply the upstream kernel patches that initialize oct->props[i].netdev before calling the queue setup functions. Fixed versions include: 5.10.250, 5.15.200, 6.1.163, 6.6.124, 6.12.70, 6.18.10, and 6.19 (stable). Patches are available via the Linux stable kernel tree. As an interim measure, restrict access to network device configuration operations to trusted administrators only (Red Hat Advisory, Amazon Linux Advisory).