Cyber Resilience

CVE-2023-21763

LPE in Microsoft Exchange Server 2016 … 2019

LPE
Published
10 January 2023
Modified
21 November 2024
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0060 46th percentile
Risk Priority 58 floored blend · peak EPSS

Summary

CVE-2023-21763 is a high-severity Untrusted Search Path (CWE-426) vulnerability in Microsoft Exchange Server. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 46th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A08:2025 Software or Data Integrity Failures

EU & UK References

Vulnerability Data

Microsoft Exchange Server Elevation of Privilege Vulnerability

CWE(s)
CWE-426NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

T1034 Path Interception Persistence
**This technique has been deprecated.
attack.mitre.org →
T1574 Hijack Execution Flow Stealth
Adversaries may execute their own malicious payloads by hijacking the way operating systems run programs.
attack.mitre.org →
T1574.001 DLL Stealth
Adversaries may abuse dynamic-link library files (DLLs) in order to achieve persistence, escalate privileges, and evade defenses.
attack.mitre.org →
T1574.008 Path Interception by Search Order Hijacking Stealth
Adversaries may execute their own malicious payloads by hijacking the search order used to load other programs.
attack.mitre.org →
T1574.007 Path Interception by PATH Environment Variable Stealth
Adversaries may execute their own malicious payloads by hijacking environment variables used to load libraries.
attack.mitre.org →
T1574.009 Path Interception by Unquoted Path Stealth
Adversaries may execute their own malicious payloads by hijacking vulnerable file path references.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-26198Same product: Microsoft Exchange Server
CVE-2023-21764Same product: Microsoft Exchange Server
CVE-2023-36778Same product: Microsoft Exchange Server
CVE-2021-26855Same product: Microsoft Exchange Server
CVE-2023-36050Same product: Microsoft Exchange Server
CVE-2022-41040Same product: Microsoft Exchange Server
CVE-2024-49040Same product: Microsoft Exchange Server
CVE-2023-35388Same product: Microsoft Exchange Server
CVE-2023-36745Same product: Microsoft Exchange Server
CVE-2021-26858Same product: Microsoft Exchange Server

Affected Assets

microsoft
exchange server
2016, 2019

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-05 full match
prevents

Preventing execution of unauthorized code directly blocks the malicious binaries that an untrusted search path would load.

PR.PS-06 mostly match
prevents

Secure development practices include avoiding or sanitizing externally influenced search paths in application code.

PR.PS-01 partial match
prevents

Hardened configuration baselines can enforce safe search paths and restrict environment variables that enable the weakness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can discover search-path issues but does not itself prevent them in production code.

A.8.19 Installation of software on operational systems partial match
degrades

Restricting software installation reduces the chance that untrusted binaries or libraries are placed in search paths.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles include hard-coded or validated search paths and avoiding reliance on untrusted directories.

A.8.28 Secure coding partial match
prevents

Secure coding standards require absolute paths or integrity-checked search paths, directly mitigating CWE-426.

A.8.32 Change management none match
none

Change-management processes can enforce review of path-handling changes, indirectly lowering risk.

References