Cyber Resilience

CVE-2023-33153

Memory Safety in Microsoft Office 2013 … 2019

Memory Safety
Published
11 July 2023
Modified
19 May 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H
EPSS Score 0.010 60th percentile
Risk Priority 59 floored blend · peak EPSS

Summary

CVE-2023-33153 is a medium-severity Use After Free (CWE-416) vulnerability in Microsoft Office. Its CVSS base score is 6.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked in the top 40% 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.

CVE-2023-33153 is a remote code execution vulnerability affecting Microsoft Outlook, as indicated by its official description and assignment of CWE-416. The flaw carries a CVSS 3.1 base score of 6.8 with the vector AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H, reflecting network-accessible attack potential that requires user interaction and high attack complexity.

An unauthenticated remote attacker can leverage the issue to execute arbitrary code on a target system, resulting in high integrity and availability impacts while leaving confidentiality unaffected. Successful exploitation therefore allows an adversary to modify data or disrupt Outlook functionality after the victim interacts with malicious content delivered over the network.

Microsoft’s Security Response Center advisory at the referenced URL supplies official mitigation guidance, including available patches and recommended update actions for affected Outlook installations.

The associated EPSS score rose materially from a low baseline after the July 2023 disclosure, reaching a peak of 0.0673 on 2025-01-22 before receding to the current value of 0.0064; this trajectory indicates that exploitation interest emerged well after public release and warrants renewed attention.

EU & UK References

Vulnerability Data

Microsoft Outlook Remote Code Execution Vulnerability

CWE(s)
CWE-416NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
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 →
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-2023-33149Same product: Microsoft 365 Apps
CVE-2025-21392Same product: Microsoft 365 Apps
CVE-2025-29792Same product: Microsoft 365 Apps
CVE-2026-40418Same product: Microsoft 365 Apps
CVE-2025-53731Same product: Microsoft 365 Apps
CVE-2024-49032Same product: Microsoft 365 Apps
CVE-2026-40419Same product: Microsoft 365 Apps
CVE-2025-27745Same product: Microsoft 365 Apps
CVE-2025-53730Same product: Microsoft 365 Apps
CVE-2023-28285Same product: Microsoft 365 Apps

Affected Assets

microsoft
365 apps
all versions
microsoft
office
2013, 2016, 2019
microsoft
office long term servicing channel
2021

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.4.3

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SI-16 Memory Protection
addresses: CWE-416

Use-after-free exploits that achieve arbitrary code execution are blocked or significantly hardened by non-executable pages and ASLR.

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 mostly match
prevents

Secure SDLC practices directly incorporate memory-safety tooling and reviews that prevent most use-after-free defects.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.

PR.PS-02 partial match
prevents

Routine patching removes known use-after-free instances after they have been introduced in released software.

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 can detect use-after-free bugs before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates memory-safety practices that reduce use-after-free defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify memory-management rules that mitigate use-after-free.

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

Secure architecture principles include memory-safety design choices that limit use-after-free exposure.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prescribe avoidance of use-after-free patterns.

A.8.32 Change management partial match
prevents

Change-management processes help ensure memory-safety fixes are deployed consistently.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 8 (1 rule)
  • V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 9 (1 rule)
  • V-257794 RHEL 9 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416

References