Cloudanix VulnDB

CVE-2026-89577

None

CVSS

—

EPSS

0.2%

Published

Sep 11, 2026

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A storage mirroring feature in Linux could fail parts of a redundant disk setup when handling unusual data requests, potentially reducing reliability until fixed.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Denial Of Service
Component
OS kernel
Class
Improper Input Validation
Remediation
Patch
Effort
Medium
Patch risk
Low

What it actually does

The vulnerability stems from improper input validation in dm-io error handling, where BLK_STS_NOTSUPP and BLK_STS_INVAL errors from unaligned bio vectors are not separated from retryable errors, causing dm-raid1 to incorrectly fail legs instead of isolating unsupported operations.

Why it matters to the business

Organizations relying on Linux device-mapper RAID1 for storage redundancy may experience unexpected array degradation, reduced availability, and potential data access disruptions under specific I/O patterns, increasing operational overhead for storage maintenance.

How an attack unfolds

An attacker with local access to submit crafted I/O requests using unaligned bio vectors against a dm-raid1 device triggers the mishandled error codes; the lack of separate error bitmaps causes the RAID1 leg to fail unnecessarily, degrading the array without requiring remote network interaction.

How to fix it

Apply the upstream Linux kernel patch that separates error_bits and unsup_bits reporting in dm-io and updates dm-raid1 to ignore unsup_bits errors; rebuild and deploy the fixed kernel across affected systems.

How to confirm the fix worked

Verify the presence of the dm-io interface change reporting separate error bitmaps and confirm dm-raid1 no longer fails legs on unsup_bits errors through code review or kernel source inspection post-update.

Typical attack path

  1. Obtain local access to a system using dm-raid1
  2. Craft and submit I/O requests with unaligned bio vectors
  3. Trigger BLK_STS_NOTSUPP or BLK_STS_INVAL error conditions
  4. Observe incorrect leg failure and array degradation

How to detect it

Review system logs for dm-raid1 leg failure events correlated with unaligned I/O patterns; examine kernel traces or device-mapper logs for repeated BLK_STS_NOTSUPP or BLK_STS_INVAL errors without corresponding hardware issues.

What your security team should do

  • Prioritize kernel updates on systems using dm-raid1 for storage
  • Monitor for unaligned bio vector usage in storage workloads as a potential trigger
  • Test RAID1 behavior under error conditions after patching

The record

In the Linux kernel, the following vulnerability has been resolved: dm-io: report non-retryable errors separatedly The error codes BLK_STS_NOTSUPP and BLK_STS_INVAL should not cause leg failure on dm-raid1. This patch changes the interface to dm-io, so that it reports two error bitmaps - error_bits and unsup_bits. The unsup_bit bitmap tracks BLK_STS_NOTSUPP or BLK_STS_INVAL errors, the error_bits bitmap tracks all the other errors. dm-raid1 is changed so that it won't fail a leg if it receives an error in the unsup_bits bitmap. This patch (with 62dc37a819a5) fixes misbehavior if the user uses unaligned bio vectors on dm-raid1.

Affected packages

Ecosystem Package Introduced Fixed