CVE-2020-0851

Code execution via HTML DOC use-after-free

Published Mar 12, 2020 · Updated Aug 4, 2024

Use-after-free in Microsoft Word allows remote attackers to execute code by opening a crafted DOC file or visiting a malicious page. During HTML-bearing DOC processing in wwlib, Word reuses a pointer after freeing its referenced object, enabling code execution in the current process. Exploitation requires the target to open the file or visit attacker-controlled content, and the resulting code runs with the target user's privileges.

CVSS severity7.8
High
EPSS probability11.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in Microsoft Word allows remote attackers to execute code by opening a crafted DOC file or visiting a malicious page. During HTML-bearing DOC processing in wwlib, Word reuses a pointer after freeing its referenced object, enabling code execution in the current process. Exploitation requires the target to open the file or visit attacker-controlled content, and the resulting code runs with the target user's privileges.

The record

CVE
CVE-2020-0851
Published
Mar 12, 2020
Updated
Aug 4, 2024
Vendor
Microsoft
Product
Microsoft Office
Classifications
T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2016 for Mac
  2. Affected versionversion=2019 for Mac

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Officeversion=2016 for Mac; version=2019 for Mac
Microsoft · Microsoft 365 Apps for enterpriseversion=32-bit Systems; version=64-bit Systems

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
9.3NIST NVDAV:N/AC:M/Au:N/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1204.002Malicious File
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo