# CVE-2026-64920: Microsoft Office Access heap-based buffer overflow

Source: https://junglewise.ai/threats/cve-2026-64920-microsoft-office-access-heap-based-buffer-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-64920 · Severity: high · CVSS 7.8 · Published 2026-08-11

Microsoft Office Access is a database management tool used for storing and managing organizational data. A heap-based buffer overflow vulnerability allows an attacker with local access to execute arbitrary code with the privileges of the user running Access, potentially compromising sensitive business data and system integrity.

Technologies: [Microsoft Office Access](https://junglewise.ai/threats/technologies/office-access). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-64920 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-64920 being exploited in the wild.

**How severe is CVE-2026-64920?** High severity, with a CVSS score of 7.8, published 11 August 2026.

**Which products and versions are affected?** Microsoft Office Access.

**Is there a fix for CVE-2026-64920?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-64920 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-64920?** Check whether you run Microsoft Office Access. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A heap-based buffer overflow exists in Microsoft Office Access that can be exploited through a maliciously crafted database file or input. The vulnerability requires local access to the system and user interaction to open a malicious file. Successful exploitation allows an attacker to execute arbitrary code in the context of the user running Access, potentially leading to system compromise. A patch is available through Microsoft Security Updates.

## Affected products

- Microsoft Office Access

## Timeline

- 2026-08-11: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64920](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64920)

## Related threats

- [Microsoft Office Access heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-111305-heap-based-buffer-overflow-in-microsoft-office-access-allows-an)
- [Microsoft Office Access heap buffer overflow](https://junglewise.ai/threats/cve-2026-111301-heap-based-buffer-overflow-in-microsoft-office-access-allows-an)
- [Microsoft Office Access heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-110060-heap-based-buffer-overflow-in-microsoft-office-access-allows-an)
- [Microsoft Office Access heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-110059-heap-based-buffer-overflow-in-microsoft-office-access-allows-an)
- [Microsoft Office Access heap buffer overflow](https://junglewise.ai/threats/cve-2026-110058-heap-based-buffer-overflow-in-microsoft-office-access-allows-an)