CVE-2023-21763

Local privilege escalation via untrusted search path

Published Jan 10, 2023 · Updated Jan 1, 2025

Untrusted search path handling in Microsoft Exchange Server 2016 and 2019 allows local users to elevate privileges via crafted code. Microsoft identifies CWE-426 but has not disclosed the affected component, searched path, or unsafe lookup operation. Exploitation requires existing low-privileged local access; successful code execution gains higher privileges, but the final privilege level is undisclosed.

CVSS severity7.8
High
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Untrusted search path handling in Microsoft Exchange Server 2016 and 2019 allows local users to elevate privileges via crafted code. Microsoft identifies CWE-426 but has not disclosed the affected component, searched path, or unsafe lookup operation. Exploitation requires existing low-privileged local access; successful code execution gains higher privileges, but the final privilege level is undisclosed.

The record

CVE
CVE-2023-21763
Published
Jan 10, 2023
Updated
Jan 1, 2025
Vendor
Microsoft
Product
Microsoft Exchange Server 2019 Cumulative Update 12
Classifications
CWE-426, 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

7.8NIST NVDCVSS:3.1/AV:L/AC:L/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

CWE-426Untrusted Search Path
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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