Cloudanix VulnDB

CVE-2023-53620

Medium · 5.5

CVSS

5.5

EPSS

0.2%

Published

Oct 7, 2025

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in Linux storage software can make the computer freeze during routine maintenance of disk arrays, requiring a restart to recover.

Exploitation
Local Privilege
Attacker needs
Low Privilege
Complexity
Low
Impact
Denial Of Service
Component
OS kernel
Class
Race Condition
Remediation
Patch
Effort
Medium
Patch risk
Low

What it actually does

Race condition between status_resync() and md_do_sync() allows concurrent reads of curr_resync and recovery_active, causing subtraction overflow that triggers an unbounded loop printing progress characters and resulting in soft lockup.

Why it matters to the business

Systems using Linux software RAID can experience sudden unresponsiveness or forced reboots during resync operations, disrupting storage services and requiring manual intervention.

How an attack unfolds

An attacker with local access triggers concurrent md device resync status queries while the kernel updates sync counters, inducing the overflow condition that hangs the reporting thread.

How to fix it

Upgrade the Linux kernel to a version containing commit b4acb6c3ede88d6b7d33742a09e63cfce5e7fb69 or later; apply vendor patches that set resync to MD_RESYNC_ACTIVE on detected overflow.

How to confirm the fix worked

Verify kernel version includes the referenced commit; monitor for absence of soft lockups during resync; test status_resync output remains bounded under concurrent access.

Typical attack path

  1. Obtain local user access on a Linux system with active md RAID arrays
  2. Initiate or observe an ongoing array resync operation
  3. Concurrently invoke status reporting interfaces to trigger the race
  4. Cause the subtraction overflow leading to excessive output loop
  5. Induce soft lockup and system degradation

How to detect it

Search kernel logs and dmesg for repeated soft lockup messages associated with md status reporting; inspect for excessive '=' characters in resync progress output under load.

What your security team should do

  • Prioritize kernel updates on systems with md RAID configurations
  • Review and apply the fixed commit across all affected distributions
  • Monitor system logs for soft lockup warnings during array operations
  • Restrict local access where possible until patches are deployed

The record

In the Linux kernel, the following vulnerability has been resolved: md: fix soft lockup in status_resync status_resync() will calculate 'curr_resync - recovery_active' to show user a progress bar like following: [============>........] resync = 61.4% 'curr_resync' and 'recovery_active' is updated in md_do_sync(), and status_resync() can read them concurrently, hence it's possible that 'curr_resync - recovery_active' can overflow to a huge number. In this case status_resync() will be stuck in the loop to print a large amount of '=', which will end up soft lockup. Fix the problem by setting 'resync' to MD_RESYNC_ACTIVE in this case, this way resync in progress will be reported to user.

Affected packages

Ecosystem Package Introduced Fixed
Linux Kernel 0 6.1.30
Linux Kernel 2.6.12 6.1.30

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