External risk intelligence

Linux Kernel md/raid10 Silent Data Corruption Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-89558

This vulnerability exists in the Linux kernel md/raid10 subsystem, which manages local storage array synchronization. It is a low-level, internal component of the operating system that is not network-accessible, does not provide an external service, and requires deep local system privileges to interact with or influence.

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory concerns a vulnerability in the Linux kernel's RAID10 component that could lead to silent data corruption if specific recovery operations are performed on a degraded array. The issue arises from an incorrect handling of a flag during device recovery, potentially causing parts of the array to be marked as synchronized with stale data.

Inaccurate data sync during RAID10 recovery.
Silent data corruption risk due to faulty recovery logic.
Confirm relevance and potential exposure within your environment.

Attack Path

How an attacker could exploit the issue

An attacker could trigger this vulnerability by manipulating the recovery process of a degraded RAID10 array. This involves intentionally failing a disk, writing data to the array while it's degraded, and then allowing the recovery process to complete. This sequence of actions leads to corrupted data being marked as synchronized, potentially resulting in silent data corruption.

Entry condition: Degraded RAID10 array.
Trigger point: Disk recovery during data writes.
Resulting risk: Silent data corruption.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could lead to silent data corruption within RAID10 arrays when recovering a disk. Under specific conditions of disk failure and recovery, the system might incorrectly mark data as synchronized, even though it contains stale information from the degraded state.

RAID10 array data integrity.
Incorrect recovery logic when disks fail.
Silent data corruption, leading to inconsistencies.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Linux kernel's md/raid10 component is affected by a vulnerability that can lead to silent data corruption during device recovery. Infrastructure and platform teams responsible for managing storage and the operating system kernel are likely to address this issue. The first practical step is to identify all systems utilizing RAID10 configurations, confirm their exposure and criticality, and then plan for remediation via kernel updates during a scheduled maintenance window.

Kernel and storage teams should own resolution.
Verify RAID10 configurations and data integrity.
Plan for kernel update during maintenance window.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

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Frequently asked questions

What is the Linux kernel md/raid10 component?

The md/raid10 component is a low-level subsystem within the Linux kernel that handles software-based RAID 10 storage. It manages how data is mirrored and striped across multiple physical disks to provide both performance and redundancy, acting as a foundational layer for managing local system storage volumes.

What does CVE-2026-89558 mean for data integrity?

This vulnerability involves a logic error where the kernel incorrectly tracks whether a RAID 10 array is still degraded during recovery. By miscalculating this status, the system may prematurely mark segments of a disk as synchronized while they actually contain outdated data, leading to silent data corruption instead of accurate restoration.

How is this RAID10 vulnerability triggered?

The flaw is triggered during the specific recovery process of a degraded RAID 10 array. It requires a sequence where a disk fails, data is written to the array while it remains in a degraded state, and the array then attempts to recover. Normal, healthy array operations or systems not using RAID 10 do not trigger this bug.

Is my system at risk according to Halo Surface Signal?

Halo Surface Signal indicates that this vulnerability is very unlikely to be remotely exploitable. Because the RAID 10 subsystem is a low-level, internal operating system component that does not provide network services and requires deep local privileges to influence, it is generally shielded from direct external network attacks.

What should I do to address CVE-2026-89558?

Begin by auditing your infrastructure to identify systems running RAID 10 configurations. Since this is a kernel-level issue, prioritize these systems for stability testing and apply the vendor-provided kernel updates during your next scheduled maintenance window to resolve the underlying recovery logic error.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.