CVE-2021-40396Public exploit

NT SYSTEM escalation via writable PostgreSQL service files

Published Jan 28, 2022 · Updated Apr 15, 2025

Privilege escalation in Advantech DeviceOn/iService 1.1.7 allows local users to execute code with NT SYSTEM privileges. The default WISE-DeviceOn installation grants Everyone full control over PostgreSQL service executables and libraries, causing replacements to load when the service restarts. Local users can first gain NETWORK SERVICE execution and then use its SeImpersonatePrivilege token privilege to reach NT SYSTEM.

CVSS severity8.8
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Advantech DeviceOn/iService 1.1.7 allows local users to execute code with NT SYSTEM privileges. The default WISE-DeviceOn installation grants Everyone full control over PostgreSQL service executables and libraries, causing replacements to load when the service restarts. Local users can first gain NETWORK SERVICE execution and then use its SeImpersonatePrivilege token privilege to reach NT SYSTEM.

The record

CVE
CVE-2021-40396
Published
Jan 28, 2022
Updated
Apr 15, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-276, T1574.010
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 28, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.2NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
8.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
8.8TalosCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/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 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 exploitPublished

Weakness, pattern, technique

CWE-276Incorrect Default Permissions
T1574.010Hijack Execution Flow: Services File Permissions Weakness

Public exploit references

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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