Cyber Resilience

CVE-2026-45645

Memory Safety in Microsoft Office 2021

Memory Safety
Published
09 June 2026
Modified
09 July 2026
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 0.0037 30th percentile
Risk Priority 57 floored blend · peak EPSS

Summary

CVE-2026-45645 is a high-severity Untrusted Pointer Dereference (CWE-822) vulnerability in Microsoft Office 2021. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 30th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Untrusted pointer dereference in Microsoft Office allows an unauthorized attacker to execute code locally.

CWE(s)
CWE-822CWE-787

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 →
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
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-2026-68810Same product: Microsoft 365 Apps
CVE-2026-45643Same product: Microsoft 365 Apps
CVE-2026-48580Same product: Microsoft 365 Apps
CVE-2026-55138Same product: Microsoft 365 Apps
CVE-2026-45471Same product: Microsoft 365 Apps
CVE-2026-55136Same product: Microsoft 365 Apps
CVE-2020-0986Same vendor: Microsoft
CVE-2015-2424Same vendor: Microsoft
CVE-2015-1641Same vendor: Microsoft
CVE-2016-7200Same vendor: Microsoft

Affected Assets

microsoft
365 apps
all versions
microsoft
microsoft 365
all versions
microsoft
office 2016
all versions
microsoft
office 2019
all versions
microsoft
office 2021
all versions
microsoft
office 2024
all versions

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover instances where untrusted data is turned into a pointer and dereferenced.

SI-10 Information Input Validation good match

Validating all information inputs stops untrusted values from being accepted and converted into dereferenceable pointers.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.

SI-16 Memory Protection partial match

Memory-protection mechanisms limit the damage from an invalid pointer dereference without stopping the root coding flaw.

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 prevent introduction of untrusted pointer handling during development.

DE.CM-09 partial match
prevents

Runtime monitoring of software and data can detect adverse events resulting from exploitation of the weakness.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover instances of this weakness via code review or scanning.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding 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 detect pointer-dereference flaws before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle includes pointer-safety practices that reduce untrusted pointer dereference risk.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate validation of pointers obtained from untrusted sources.

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

Secure architecture principles discourage direct use of untrusted values as pointers.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid dereferencing pointers derived from untrusted input.

A.8.32 Change management partial match
prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References