CVE-2020-16947

HIGH

Microsoft Outlook - Remote Code Execution via Crafted File

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2020-16947. PoCs published by 0neb1n, MasterSploit.

AI-analyzed exploit summary This repository contains a detailed writeup of CVE-2020-16947, a buffer overflow vulnerability in Outlook 2019 (16.0.13231.20262) on Windows 10 1909 x64. The vulnerability occurs during HTML content parsing, where strings outside the ASCII range are replaced with 0xfffd, leading to a buffer overflow due to size mismanagement.

Description

<p>A remote code execution vulnerability exists in Microsoft Outlook software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the targeted user. If the targeted user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.</p> <p>Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Outlook software. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.</p> <p>Note that where severity is indicated as Critical in the Affected Products table, the Preview Pane is an attack vector.</p> <p>The security update addresses the vulnerability by correcting how Outlook handles objects in memory.</p>

Exploits (2)

nomisec WRITEUP 123 stars
by 0neb1n · poc
https://github.com/0neb1n/CVE-2020-16947

This repository contains a detailed writeup of CVE-2020-16947, a buffer overflow vulnerability in Outlook 2019 (16.0.13231.20262) on Windows 10 1909 x64. The vulnerability occurs during HTML content parsing, where strings outside the ASCII range are replaced with 0xfffd, leading to a buffer overflow due to size mismanagement.

Classification
Writeup 90%
Attack Type
Rce
Complexity
Moderate
Reliability
Theoretical
Target: Microsoft Outlook 2019 (16.0.13231.20262)
No auth needed
Prerequisites: Victim must open a specially crafted HTML email in Outlook 2019
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WRITEUP 2 stars
by MasterSploit · poc
https://github.com/MasterSploit/CVE-2020-16947

The repository contains a README describing CVE-2020-16947, a buffer overflow vulnerability in Outlook 2019 due to improper handling of non-ASCII characters in HTML content. No exploit code is provided, only a high-level description and a contact email for potential 0-day exploits.

Classification
Writeup 30%
Attack Type
Rce
Complexity
Theoretical
Reliability
Theoretical
Target: Microsoft Outlook 2019
No auth needed
Prerequisites: Victim interaction (e.g., opening a malicious email)
devstral-2 · analyzed Feb 16, 2026 Full analysis →

Scores

CVSS v3 7.5
EPSS 0.3355
EPSS Percentile 98.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Details

CWE
CWE-125 CWE-787
Status published
Products (3)
microsoft/365_apps
microsoft/office 2019
microsoft/outlook 2016
Published Oct 16, 2020
Tracked Since Feb 18, 2026