# CVE-2026-78512: Microsoft Office Word numeric truncation remote code execution

Source: https://junglewise.ai/threats/cve-2026-78512-microsoft-office-word-numeric-truncation-remote-code-execution  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-08. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-78512 · Severity: high · CVSS 8.8 · Published 2026-09-08

Microsoft Office Word is a widely-used word processing application found in millions of PCs and business environments. A numeric truncation error in Word can be exploited by an attacker to execute arbitrary code on a user's computer, potentially leading to data theft, malware installation, or system compromise.

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

## Quick answers

**Is CVE-2026-78512 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-78512 being exploited in the wild.

**How severe is CVE-2026-78512?** High severity, with a CVSS score of 8.8, published 8 September 2026.

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

**Is there a fix for CVE-2026-78512?** 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-2026-78512 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-78512?** Check whether you run Microsoft Office Word. 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 numeric truncation error in Microsoft Office Word's document parsing logic allows remote code execution. An attacker can craft a malicious Word document that, when opened by a victim, triggers the vulnerability through a network-accessible mechanism. The vulnerability permits unauthenticated remote code execution with no reported user interaction bypass requirement. No patch availability information is currently confirmed in the provided advisory text.

## Affected products

- Microsoft Office Word

## Timeline

- 2026-09-08: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78512](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78512)

## Related threats

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- [Microsoft Office Word use of uninitialized resource](https://junglewise.ai/threats/cve-2026-124185-use-of-uninitialized-resource-in-microsoft-office-word-allows-an)
- [Microsoft Office Word heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123394-heap-based-buffer-overflow-in-microsoft-office-word-allows-an)
- [Microsoft Office Word heap buffer overflow](https://junglewise.ai/threats/cve-2026-116925-heap-based-buffer-overflow-in-microsoft-office-word-allows-an)
- [Microsoft Office Word heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-116923-heap-based-buffer-overflow-in-microsoft-office-word-allows-an)