CVE-2023-6340

System crash via sfpmonitor.sys kernel-memory overwrite

Published Jan 17, 2024 · Updated Jun 11, 2025

Stack-based buffer overflow in SonicWall Capture Client 3.7.10 and NetExtender 10.2.337 and earlier allows local users to crash Windows. The sfpmonitor.sys application-communication handler accepts a crafted query that overwrites kernel memory. Exploitation requires local low-privileged access; the confirmed impact is a system crash, although SonicWall also reports possible code execution.

CVSS severity5.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in SonicWall Capture Client 3.7.10 and NetExtender 10.2.337 and earlier allows local users to crash Windows. The sfpmonitor.sys application-communication handler accepts a crafted query that overwrites kernel memory. Exploitation requires local low-privileged access; the confirmed impact is a system crash, although SonicWall also reports possible code execution.

The record

CVE
CVE-2023-6340
Published
Jan 17, 2024
Updated
Jun 11, 2025
Vendor
SonicWall
Product
NetExtender
Classifications
CWE-787, CWE-121, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 17, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 11, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=10.2.337 and earlier versions

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

SonicWall · NetExtenderversion=10.2.337 and earlier versions
SonicWall · Capture Clientversion=3.7.10 and earlier versions

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-121Stack-based Buffer Overflow
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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