---
id: "CVE-2026-123378"
page: "https://infrastack.ai/live/CVE-2026-123378"
kind: "vulnerability"
aliases: ["CVE-2026-123378"]
title: "Microsoft Outlook: integer overflow lets an unauthorized attacker run code"
severity: "high"
cvss: 7.5
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["microsoft-office", "outlook", "package", "windows"]
not_affected_if: []
published_at: "2026-11-10T19:20:41+00:00"
first_seen_at: "2026-11-10T19:25:12+00:00"
updated_at: "2026-11-10T19:44:18+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123378", "first_seen_at": "2026-11-10T19:25:12+00:00"}]
exploit_sources: []
---

# Microsoft Outlook: integer overflow lets an unauthorized attacker run code

Link for people: https://infrastack.ai/live/CVE-2026-123378 (this .md is for agents)

An integer overflow in Microsoft Office Outlook can be triggered by an unauthorized attacker over the network. The sources say this allows code execution, with a CVSS score of 7.5.

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

## Timeline

- 2026-11-10T19:25:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123378

## From the sources

Integer overflow or wraparound in Microsoft Office Outlook 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_