Security Resilience

CVE-2026-97008

Memory Safety in Microsoft Office 2021

Published
13 October 2026
Modified
14 October 2026
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0072 53th percentile
Risk Priority 65 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-97008 is a high-severity Buffer Underflow (CWE-124) vulnerability in Microsoft Office 2021. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 47% of CVEs by exploit likelihood; 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

Buffer underwrite ('buffer underflow') in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
T1010 Application Window Discovery Discovery
Adversaries may attempt to get a listing of open application windows.
T1011 Exfiltration Over Other Network Medium Exfiltration
Adversaries may attempt to exfiltrate data over a different network medium than the command and control channel.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2015-2426Same vendor: Microsoft
CVE-2024-52990Same vendor: Microsoft
CVE-2023-35311Same product: Microsoft 365 Apps
CVE-2023-36896Same product: Microsoft 365 Apps
CVE-2023-33133Same product: Microsoft 365 Apps
CVE-2023-35371Same product: Microsoft 365 Apps
CVE-2023-33162Same product: Microsoft 365 Apps
CVE-2023-24953Same product: Microsoft 365 Apps
CVE-2024-43465Same product: Microsoft 365 Apps
CVE-2024-30042Same product: Microsoft 365 Apps

Affected Assets

microsoft
365 apps
all versions
microsoft
microsoft 365
all versions
microsoft
office 2021
all versions
microsoft
office 2024
all versions
microsoft
office online server
≤ 16.0.10417.20228

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 800-53 r5) AI

Developer testing and analysis can discover buffer underwrite flaws before deployment but does not stop their introduction.

Input validation can enforce bounds on indices or pointers before buffer writes, structurally stopping underwrite conditions.

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.

ID.RA-01 partial match
blocks

Vulnerability identification processes can discover buffer underwrite issues but do not prevent their creation.

PR.PS-02 partial match
blocks

Patching removes instances of the weakness after discovery but does not address root-cause prevention in code.

PR.PS-06 partial match
blocks

Secure SDLC practices directly prevent introduction of buffer underwrite flaws via coding standards, reviews, and testing.

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.

blocks

A.8.25 mandates secure SDLC practices (secure coding guidelines, security requirements, checkpoints, testing, developer training) that reach buffer management and can stop underwrite defects from being introduced, but this is only a minority slice of the weakness class because many instances arise from non-SDLC factors like unsafe third-party libraries, runtime misconfigurations, or legacy code not redeveloped under the process.

blocks

Application security requirements can specify buffer-size and pointer-safety rules.

blocks

Secure architecture and engineering principles require safe memory-handling patterns.

prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds checks.

finds

Security testing in development catches buffer-underflow defects before release.

References