---
id: "CVE-2019-0703"
kind: "vulnerability"
aliases: ["CVE-2019-0703"]
title: "Microsoft Windows: Microsoft Windows SMB Information Disclosure Vulnerability"
severity: "medium"
cvss: 6.5
epss: 0.09385
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Windows", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "file-servers", "infrastructure", "smb", "windows"]
not_affected_if: ["patched-windows", "smb-disabled"]
published_at: "2019-04-09T00:29:00+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2019-0703", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2019-0703", "first_seen_at": "2026-10-23T19:13:45+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2019-0703", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Microsoft Windows: Microsoft Windows SMB Information Disclosure Vulnerability

A flaw in how the Windows SMB Server handles certain requests lets an attacker read information from the server. CISA lists it as actively exploited in the wild.

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

## Affected

- vendor:Microsoft Windows affected ? fixed ?

## Fix

Apply the Microsoft update for CVE-2019-0703 per vendor instructions; exact KB numbers are not in the sources.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2019-0703
- 2026-10-23T19:13:45+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2019-0703
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2019-0703

## From the sources

An information disclosure vulnerability exists in the way that the Windows SMB Server handles certain requests, which could lead to information disclosure from the server.

CISA required action: Apply updates per vendor instructions.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_