CVE-2026-86848 in DPDK
Summary
by MITRE • 10/14/2026
A flaw was found in DPDK lib/vhost vhost-crypto. The indirect-descriptor snapshot double-fetches a guest descriptor next index, allowing a malicious guest to cause an out-of-bounds access in the host backend.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified within the Data Plane Development Kit (DPDK) specifically affects the libvhost component's crypto subsystem, known as vhost-crypto. This flaw stems from a fundamental race condition involving memory descriptor handling between the virtual machine guest and the hypervisor or host backend. In DPDK-based virtualized environments, network packets are often processed using indirect descriptors to optimize performance by allowing multiple segments of data to be referenced through a single descriptor entry. The core technical issue arises during the snapshotting process for these indirect descriptors. When the system captures a state or processes a batch of descriptors, it retrieves the next index from the guest's memory space. However, this retrieval is not atomic with respect to subsequent operations that rely on that same value. This creates a window where the descriptor data can be modified by the malicious guest between the initial read and its actual usage in host-side processing logic.
This specific implementation error constitutes a classic double-fetch vulnerability, which is categorized under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization of Accesses. The attacker, operating within the context of a compromised or untrusted virtual machine guest, can exploit this timing gap by rapidly modifying the descriptor's next index field in memory after it has been fetched but before it is fully processed by the host backend. Because the vhost-crypto module assumes that the data retrieved from the guest remains static during its processing cycle, the modification leads to a state inconsistency where the host attempts to access memory locations based on stale or manipulated indices. This misalignment directly results in an out-of-bounds memory access within the host's address space.
The operational impact of this vulnerability is severe due to its potential for privilege escalation and system compromise. An out-of-bounds read can lead to information disclosure, allowing a malicious guest to leak sensitive data from other virtual machines or the hypervisor itself by reading unintended memory regions. More critically, if the malformed index leads to an out-of-bounds write operation, it enables arbitrary code execution on the host backend with the privileges of the DPDK process. This effectively breaks the isolation boundary between the guest and the host, allowing a low-privilege virtual machine to gain control over the underlying physical server infrastructure. Such scenarios align closely with MITRE ATT&CK techniques related to privilege escalation and lateral movement within cloud or data center environments, particularly those involving hypervisor escape vectors via shared memory interfaces like virtio-vhost.
Mitigation strategies must address both immediate remediation and long-term architectural hardening. The primary solution is to apply the vendor-provided patches that update the libvhost library to versions where the descriptor snapshotting logic has been corrected to ensure atomicity or proper locking mechanisms are in place during index retrieval. Administrators should verify their DPDK version against known vulnerable ranges and upgrade accordingly. Beyond software updates, defense-in-depth measures include enabling strict memory protection features such as Intel VT-d or AMD-Vi IOMMU configurations to limit the DMA capabilities of virtual devices, thereby restricting the guest's ability to manipulate host memory directly even if a logical flaw is exploited. Additionally, deploying runtime application self-protection (RASP) tools and monitoring for anomalous memory access patterns in DPDK processes can help detect exploitation attempts in real-time before significant damage occurs.