CVE-2023-21764

SYSTEM privilege escalation via unsecured library search

Published Jan 10, 2023 · Updated Jan 1, 2025

Local privilege escalation in affected Microsoft Exchange Server 2016 and 2019 builds allows local users to execute code as SYSTEM. GetTorusCmdletConfigurationEntries loads a library from an unsecured search location, allowing an attacker-controlled DLL to run in its privileged context. Exploitation requires prior low-privileged code execution on the Exchange host and grants full SYSTEM-level code execution.

CVSS severity7.8
High
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Local privilege escalation in affected Microsoft Exchange Server 2016 and 2019 builds allows local users to execute code as SYSTEM. GetTorusCmdletConfigurationEntries loads a library from an unsecured search location, allowing an attacker-controlled DLL to run in its privileged context. Exploitation requires prior low-privileged code execution on the Exchange host and grants full SYSTEM-level code execution.

The record

CVE
CVE-2023-21764
Published
Jan 10, 2023
Updated
Jan 1, 2025
Vendor
Microsoft
Product
Microsoft Exchange Server 2019 Cumulative Update 12
Classifications
T1574.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 1, 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=15.02.0 <15.02.1118.021

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft Exchange Server 2019 Cumulative Update 12version=15.02.0 <15.02.1118.021
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 11version=15.02.0 <15.02.0986.037
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 23version=15.01.0 <15.01.2507.017

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Trend Micro Zero Day InitiativeCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/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 exploitUnconfirmed

Weakness, pattern, technique

T1574.001Hijack Execution Flow: DLL

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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