Cyber Resilience

CVE-2023-33133

Memory Safety in Microsoft Excel 2013 … 2016

Memory Safety
Published
14 June 2023
Modified
04 November 2025
Patch / advisory
View advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.44 99th percentile
Risk Priority 76 floored blend · peak EPSS

Summary

CVE-2023-33133 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Excel. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

Microsoft Excel contains a remote code execution vulnerability tracked as CVE-2023-33133 and assigned a CVSS score of 7.8. The flaw is associated with CWE-122 and affects the application's handling of certain inputs, enabling code execution when a crafted document is processed.

An unauthenticated attacker can exploit the issue by supplying a malicious Excel file that a user must open locally. Successful exploitation grants high-impact control over confidentiality, integrity, and availability on the target system without requiring elevated privileges.

Microsoft has published remediation guidance in its Security Response Center advisory for this vulnerability, and additional technical analysis is available from Cisco Talos. The associated EPSS score has remained at 0.3721 since disclosure with no material increase observed.

EU & UK References

Vulnerability Data

Microsoft Excel Remote Code Execution Vulnerability

CWE(s)
CWE-122NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-40362Same product: Microsoft 365 Apps
CVE-2025-54900Same product: Microsoft 365 Apps
CVE-2025-21390Same product: Microsoft 365 Apps
CVE-2025-62201Same product: Microsoft 365 Apps
CVE-2023-36896Same product: Microsoft 365 Apps
CVE-2024-49030Same product: Microsoft 365 Apps
CVE-2026-20957Same product: Microsoft 365 Apps
CVE-2025-47174Same product: Microsoft 365 Apps
CVE-2025-49697Same product: Microsoft 365 Apps
CVE-2024-38172Same product: Microsoft 365 Apps

Affected Assets

microsoft
365 apps
all versions
microsoft
excel
2013, 2016
microsoft
office long term servicing channel
2021
microsoft
office online server
all versions

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

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-06 full match
prevents

Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover heap-overflow flaws but does not prevent their introduction in code.

PR.PS-02 partial match
prevents

Timely patching removes known heap-overflow instances after they exist.

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 in development and acceptance can detect heap overflows before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates practices that reduce the likelihood of introducing heap overflows.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify bounds-checking and safe memory APIs that mitigate heap overflows.

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

Secure architecture and engineering principles include memory-safety and input-validation controls that address heap overflows.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prescribe techniques (safe functions, bounds checks) that prevent heap-based buffer overflows.

A.8.32 Change management none match
none

Change management ensures controlled deployment of fixes for discovered heap-overflow vulnerabilities.

References