CVE-2025-21690

VM denial of service via unthrottled SCSI warnings

Published Feb 10, 2025 · Updated May 11, 2026

Resource exhaustion in affected Linux kernel releases allows local users to interrupt a Hyper-V guest through persistent failed SCSI I/O. The storvsc_on_io_completion() function sends every failed-I/O warning through an unthrottled storvsc_log() call, allowing a persistent hypervisor error to flood the kernel log and consume available CPU time. Exploitation requires local low-privileged access in a guest using the Hyper-V SCSI driver; the result is VM denial of service and loss of guest-side troubleshooting.

CVSS severity5.5
Medium
EPSS probability0.21%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in affected Linux kernel releases allows local users to interrupt a Hyper-V guest through persistent failed SCSI I/O. The storvsc_on_io_completion() function sends every failed-I/O warning through an unthrottled storvsc_log() call, allowing a persistent hypervisor error to flood the kernel log and consume available CPU time. Exploitation requires local low-privileged access in a guest using the Hyper-V SCSI driver; the result is VM denial of service and loss of guest-side troubleshooting.

The record

CVE
CVE-2025-21690
Published
Feb 10, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-770, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 10, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.5
  2. Affected versionversion=f8aea701b77c26732f151aab4f0a70e62eb53d86 <01d1ebdab9ccb73c952e1666a8a80abd194dbc55
  3. Affected versionversion=f8aea701b77c26732f151aab4f0a70e62eb53d86 <088bde862f8d3d0fc52e40e66a0484a246837087
  4. Affected versionversion=f8aea701b77c26732f151aab4f0a70e62eb53d86 <182a4b7c731e95c08cb47f14b87a272b6ab2b2da
  5. Affected versionversion=f8aea701b77c26732f151aab4f0a70e62eb53d86 <81d4dd05c412ba04f9f6b85b718e6da833be290c
  6. Affected versionversion=f8aea701b77c26732f151aab4f0a70e62eb53d86 <d0f0af1bafef33b3e2aa8c3a4ef44db48df9b0ea
  7. Affected versionversion=f8aea701b77c26732f151aab4f0a70e62eb53d86 <d2138eab8cde61e0e6f62d0713e45202e8457d6d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.5; version=f8aea701b77c26732f151aab4f0a70e62eb53d86 <01d1ebdab9ccb73c952e1666a8a80abd194dbc55; version=f8aea701b77c26732f151aab4f0a70e62eb53d86 <088bde862f8d3d0fc52e40e66a0484a246837087; version=f8aea701b77c26732f151aab4f0a70e62eb53d86 <182a4b7c731e95c08cb47f14b87a272b6ab2b2da; version=f8aea701b77c26732f151aab4f0a70e62eb53d86 <81d4dd05c412ba04f9f6b85b718e6da833be290c; version=f8aea701b77c26732f151aab4f0a70e62eb53d86 <d0f0af1bafef33b3e2aa8c3a4ef44db48df9b0ea; version=f8aea701b77c26732f151aab4f0a70e62eb53d86 <d2138eab8cde61e0e6f62d0713e45202e8457d6d

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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