CVE-2026-99047 in Linux
Summary
by MITRE • 10/23/2026
In the Linux kernel, the following vulnerability has been resolved:
gve: fix XSK buffer leak when rings are stopped
GVE does not free XSK buffers when resetting ring state as a part of stopping queues. This causes all XSK buffers which are posted to the NIC to be leaked.
Free XSK buffers attached to an allocated buf_state when stopping rings.
This issue was hit in production.
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Analysis
by VulDB Data Team • 10/23/2026
The General Virtual Ethernet driver, known as gve, serves as a critical network interface component for Google Cloud virtual machines running Linux kernels. This specific vulnerability addresses a resource management flaw within the driver's handling of eXpress Data Path (XDP) sockets and their associated buffer rings. When the network queues are stopped or reset, typically during link state changes, driver resets, or administrative interventions such as bringing an interface down, the gve driver fails to properly release the memory buffers allocated for XSK operations. This oversight results in a direct leak of kernel memory resources that were previously assigned to hardware descriptor rings but remain unreleased upon ring termination.
From a technical perspective, the flaw resides in the cleanup logic executed when transitioning queue states from active to stopped. The driver allocates buffer structures to facilitate high-performance packet processing via XDP sockets, which allow for zero-copy data transfer between user space and kernel space. When the rings are halted, the expected behavior is to iterate through all pending or completed buffers attached to the buf_state structure and free them back to the system memory pool. However, due to a missing deallocation step in this specific code path, these buffer descriptors remain allocated but orphaned from active processing cycles. This constitutes an improper resource cleanup mechanism where resources are acquired during initialization or packet transmission phases but not returned upon termination of the associated hardware context.
The operational impact of this vulnerability is primarily characterized by progressive kernel memory exhaustion and potential system instability over time. Since each stopped ring retains its allocated XSK buffers, repeated occurrences of queue resets can lead to a steady accumulation of leaked physical pages in the kernel heap. In production environments where network interfaces may undergo frequent state changes due to load balancing events, failover scenarios, or automated scaling operations, this leak accelerates significantly. Over extended periods, the cumulative memory loss can degrade overall system performance by increasing pressure on the page allocator and potentially triggering out-of-memory conditions if sufficient swap space is not available. While immediate denial of service through total kernel panic may require significant trigger frequency, the gradual degradation poses a serious risk to long-running services relying on high-throughput network connectivity via XDP acceleration.
This vulnerability aligns with Common Weakness Enumeration category CWE-401, which describes missing release of memory after effective usage. The failure to free allocated resources represents a classic resource management error that undermines system reliability and security posture by reducing the available entropy and computational capacity for other critical processes. Furthermore, in the context of attack surface analysis, such as MITRE ATT&CK techniques related to Resource Hijacking or Impact through Denial of Service, this flaw provides an avenue for local attackers with sufficient privileges to induce memory pressure attacks against the host system. By repeatedly triggering network interface resets, a malicious actor could theoretically accelerate resource depletion, contributing to service degradation across co-located workloads on the same physical hardware.
Mitigation strategies focus primarily on applying vendor-provided kernel patches that correct the buffer deallocation logic within the gve driver source code. System administrators should ensure their Linux kernels are updated to versions where this fix is integrated into the mainline or stable release branches. In environments where immediate patching is not feasible, operational mitigations include minimizing unnecessary network interface resets and avoiding frequent toggling of link states in production workloads that rely heavily on XDP acceleration. Monitoring kernel memory usage trends for gve-related allocations can also serve as an early warning indicator for the presence of this leak before it reaches critical thresholds affecting system stability.