CVE-2020-0908 — Windows Text Service Module Remote Code Execution Vulnerability

Executive Summary

A remote code execution vulnerability exists when the Windows Text Service Module improperly handles memory. An attacker who successfully exploited the vulnerability could gain execution on a victim system. An attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft Edge (Chromium-based), and then convince a user to view the website. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements by adding specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by way of enticement in an email or Instant Messenger message, or by getting them to open an attachment sent through email. The security update addresses the vulnerability by correcting how the Windows Text Service Module handles memory.

Overview

7.5

CVSS HIGH

Critical

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Remote Code Execution

Released Sep 8 2020

Last Updated Sep 8 2020

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.03264 — 0.86771 percentile

NVD CVSS 7.5 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C

ATTACK VECTOR

Network

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

None

USER INTERACTION

Required

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 6.7

EPSS Score

0.03264

probability of exploitation in the next 30 days

0.86771 percentile - updated 2026-06-21

View on FIRST.org

Affected Products

27 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1607 for 32-bit Systems	`4577015 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1607 for x64-based Systems	`4577015 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1709 for 32-bit Systems	`4577041 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1709 for ARM64-based Systems	`4577041 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1709 for x64-based Systems	`4577041 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1803 for 32-bit Systems	`4577032 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1803 for ARM64-based Systems	`4577032 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1803 for x64-based Systems	`4577032 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1809 for 32-bit Systems	`4570333 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1809 for ARM64-based Systems	`4570333 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1809 for x64-based Systems	`4570333 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1903 for 32-bit Systems	`4574727 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1903 for ARM64-based Systems	`4574727 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1903 for x64-based Systems	`4574727 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1909 for 32-bit Systems	`4574727 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1909 for ARM64-based Systems	`4574727 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1909 for x64-based Systems	`4574727 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 2004 for 32-bit Systems	`4571756 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 2004 for ARM64-based Systems	`4571756 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 2004 for x64-based Systems	`4571756 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2016	`4577015 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2016 (Server Core installation)	`4577015 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2019	`4570333 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2019 (Server Core installation)	`4570333 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server, version 1903 (Server Core installation)	`4574727 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server, version 1909 (Server Core installation)	`4574727 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server, version 2004 (Server Core installation)	`4571756 (Security Update)`	Critical	Remote Code Execution	Yes

Patches

6 patches

Article	Type	Restart
`4577015`	Security Update	Yes
`4577041`	Security Update	Yes
`4577032`	Security Update	Yes
`4570333`	Security Update	Yes
`4574727`	Security Update	Yes
`4571756`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Liu Long of Ant Group Light-Year Security Lab, Trend Micro's Zero Day Initiative

References

MSRC Advisory MITRE NVD