CVE-2026-23023: Linux Kernel Use-After-Free Vulnerability

CVE-2026-23023 Overview

CVE-2026-23023 is a Memory Leak vulnerability in the Linux kernel's IDPF (Infrastructure Data Plane Function) network driver. The vulnerability exists in the idpf_vport_rel() function, which fails to properly free the vport->rx_ptype_lkup memory allocation during virtual port release operations. This results in memory leakage during device reset cycles, potentially leading to system resource exhaustion over time.

Critical Impact

Memory resources are not properly deallocated during IDPF device resets, which can lead to gradual system memory exhaustion and potential denial of service conditions on affected Linux systems utilizing the IDPF network driver.

Affected Products

• Linux kernel with IDPF network driver module
• Systems using Intel Infrastructure Data Plane Function devices
• Linux kernel versions prior to the security patch

Discovery Timeline

• 2026-01-31 - CVE CVE-2026-23023 published to NVD
• 2026-02-03 - Last updated in NVD database

Technical Details for CVE-2026-23023

Vulnerability Analysis

This vulnerability represents a classic memory leak pattern in kernel driver code. When the IDPF driver initializes a virtual port, it allocates memory for the rx_ptype_lkup (receive packet type lookup) table via idpf_send_get_rx_ptype_msg(). The memory allocation is performed through __kmalloc_cache_noprof(), allocating 4096 bytes for the lookup table structure.

The issue manifests when the virtual port is released through idpf_vport_rel() during device reset operations. The function neglects to call the corresponding free operation for the vport->rx_ptype_lkup allocation, causing the memory to become unreferenced and unrecoverable. The Linux kernel's kmemleak detection facility identified this leak, capturing the full allocation backtrace from the initial idpf_init_task worker thread through to the kernel memory allocator.

Root Cause

The root cause is a missing memory deallocation call in the idpf_vport_rel() cleanup function. While the IDPF driver properly allocates memory for the rx_ptype_lkup structure during virtual port initialization, the corresponding cleanup path does not include a kfree() call to release this memory when the virtual port is destroyed. This is a common pattern of error in kernel driver development where allocation and deallocation paths become misaligned, particularly in error handling and reset code paths.

Attack Vector

The vulnerability has an unknown attack vector classification. As a memory leak vulnerability, exploitation would require triggering repeated IDPF device reset operations to gradually exhaust available kernel memory. While this is primarily a reliability and stability issue rather than a direct security exploit, persistent memory exhaustion could lead to denial of service conditions.

The memory leak occurs through the following execution path:

• The kernel workqueue worker thread executes idpf_init_task()
• This calls idpf_send_get_rx_ptype_msg() which allocates 4096 bytes via __kmalloc_cache_noprof()
• When a reset occurs and idpf_vport_rel() is called, the allocated memory is not freed
• Each subsequent reset cycle leaks an additional 4096 bytes of kernel memory

Detection Methods for CVE-2026-23023

Indicators of Compromise

• Kernel memory leak reports from kmemleak showing unreferenced objects related to IDPF driver
• Gradual increase in kernel memory usage on systems with active IDPF network devices
• Memory allocation backtraces referencing idpf_send_get_rx_ptype_msg() and idpf_init_task()
• System memory pressure symptoms following multiple IDPF device reset cycles

Detection Strategies

• Enable and monitor the Linux kernel's kmemleak feature (/sys/kernel/debug/kmemleak)
• Audit /proc/meminfo for unexplained growth in kernel slab memory allocations
• Monitor system logs for IDPF driver reset events and correlate with memory usage patterns
• Use kernel tracing tools to track kmalloc/kfree balance in the IDPF driver module

Monitoring Recommendations

• Implement proactive monitoring of kernel memory statistics on systems using IDPF network interfaces
• Configure alerts for abnormal growth in slab memory allocations
• Deploy SentinelOne agents to monitor for system stability issues related to memory exhaustion
• Establish baseline memory usage patterns for IDPF-equipped systems to identify anomalies

How to Mitigate CVE-2026-23023

Immediate Actions Required

• Review systems for IDPF driver usage and assess exposure to this vulnerability
• Apply the Linux kernel security patches from the official kernel git repository
• Minimize unnecessary device reset operations on affected IDPF network interfaces
• Monitor memory utilization on affected systems until patches can be deployed

Patch Information

The vulnerability has been addressed through patches committed to the stable Linux kernel tree. The fixes ensure that vport->rx_ptype_lkup is properly freed in the idpf_vport_rel() function. The patches are available at the following kernel git commits:

• Kernel Git Commit Details
• Kernel Git Commit Changes
• Kernel Git Commit Summary

Workarounds

• Avoid triggering IDPF device resets when possible until the patch is applied
• Periodically reboot affected systems to reclaim leaked memory if patching is delayed
• Consider temporarily disabling or replacing IDPF network interfaces with alternative drivers if available
• Implement system monitoring to detect and respond to memory pressure conditions