---
id: "CVE-2026-123385"
page: "https://infrastack.ai/live/CVE-2026-123385"
kind: "vulnerability"
aliases: ["CVE-2026-123385"]
title: "Microsoft Excel: stack buffer overflow lets an attacker run code remotely"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "Microsoft Office Excel", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["excel", "microsoft-office", "other", "user-interaction-required", "windows"]
not_affected_if: []
published_at: "2026-11-10T19:20:42+00:00"
first_seen_at: "2026-11-10T19:25:12+00:00"
updated_at: "2026-11-10T21:32:04+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123385", "first_seen_at": "2026-11-10T19:25:12+00:00"}, {"source": "analyst", "url": "https://www.rapid7.com/db/vulnerabilities/cve-2026-123385/", "first_seen_at": "2026-11-10T21:32:04+00:00", "cites": ["https://www.rapid7.com/db/vulnerabilities/cve-2026-123385/"]}]
exploit_sources: []
---

# Microsoft Excel: stack buffer overflow lets an attacker run code remotely

Link for people: https://infrastack.ai/live/CVE-2026-123385 (this .md is for agents)

A stack-based buffer overflow in Microsoft Excel can be triggered over a network by an unauthorized attacker. A successful attack lets the attacker execute code on the victim's machine.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Microsoft Office Excel affected range not listed fixed no fixed version listed

## How to check

Unknown until Microsoft's advisory lists builds. Check Excel build under File > Account > About Excel and compare to the MSRC Security Update Guide entry for CVE-2026-123385.

## Fix

Unknown: no fixed build read from a Microsoft source yet. Apply Microsoft Office updates once the MSRC entry lists one.

## Timeline

- 2026-11-10T19:25:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123385
- 2026-11-10T21:32:04+00:00 analyst https://www.rapid7.com/db/vulnerabilities/cve-2026-123385/ — MSRC update guide is JS-only and returned no text; no Microsoft primary page read, so affected builds and fixed versions are unknown. Only NVD/Rapid7 CVSS vector (AV:N, UI:R: victim must open/interact with a file). Not in KEV, no PoC found. Nothing verified. Settle by reading the MSRC guide entry for this CVE (or the Nov 2026 Patch Tuesday notes).

## Documents

- [describes] Rapid7 DB: CVE-2026-123385 https://www.rapid7.com/db/vulnerabilities/cve-2026-123385/

## From the sources

Stack-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_