Internet Explorer Remote Code Execution Vulnerability

Summary

CVE	CVE-2021-27085
State	PUBLISHED
Assigner	microsoft
Source Priority	CVE Program / NVD first with legacy fallback
Published	2021-03-11 16:15:18 UTC
Updated	2026-08-19 19:22:43 UTC
Description	Internet Explorer Remote Code Execution Vulnerability

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS: 0.054480000 probability, percentile 0.921180000 (date 2026-08-21)

CISA KEV: Listed on 2021-11-03; due 2021-11-17; ransomware use Unknown

Problem Types: NVD-CWE-noinfo | Remote Code Execution | CWE-noinfo Not enough information

Version	Source	Type	Score	Severity	Vector
3.1	[email protected]	Secondary	8.8	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`
3.1	[email protected]	Secondary	8.8	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L`
3.1	CNA	CVSS	8.8	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L/E:P/RL:O/RC:C`
2.0	[email protected]	Primary	7.6		`AV:N/AC:H/Au:N/C:C/I:C/A:C`

CVSS v3.1 Breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v2.0 Breakdown

Access Vector

Network

Access Complexity

High

Authentication

None

Confidentiality

Complete

Integrity

Complete

Availability

Complete

AV:N/AC:H/Au:N/C:C/I:C/A:C

CISA Known Exploited Vulnerability

Vendor	Microsoft
Product	Internet Explorer
Name	Microsoft Internet Explorer Remote Code Execution Vulnerability
Required Action	Apply updates per vendor instructions.
Notes	https://nvd.nist.gov/vuln/detail/CVE-2021-27085

NVD Known Affected Configurations (CPE 2.3)

Type	Vendor	Product	Version	Update	Edition	Language
Application	Microsoft	Internet Explorer	11	-	All	All
Operating System	Microsoft	Windows 10 1803	-	All	All	All
Operating System	Microsoft	Windows 10 1809	-	All	All	All
Operating System	Microsoft	Windows 10 1909	-	All	All	All
Operating System	Microsoft	Windows 10 2004	-	All	All	All
Operating System	Microsoft	Windows 10 20h2	-	All	All	All
Operating System	Microsoft	Windows Server 2019	-	All	All	All

Vendor Declared Affected Products

Source	Vendor	Product	Version	Platforms
CNA	Microsoft	Internet Explorer 11	affected 1.0.0 10.0.17134.2087 custom	Windows 10 Version 1803 for 32-bit Systems, Windows 10 Version 1803 for ARM64-based Systems, Windows 10 Version 1803 for x64-based Systems, Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for ARM64-based Systems, Windows 10 Version 1809 for x64-based Systems, Windows 10 Version 1909 for 32-bit Systems, Windows 10 Version 1909 for ARM64-based Systems, Windows 10 Version 1909 for x64-based Systems, Windows 10 Version 2004 for 32-bit Systems, Windows 10 Version 2004 for ARM64-based Systems, Windows 10 Version 2004 for x64-based Systems, Windows 10 Version 20H2 for 32-bit Systems, Windows 10 Version 20H2 for ARM64-based Systems, Windows Server 2019

References

Reference	Source	Link	Tags
msrc.microsoft.com/update-guide/vulnerability/CVE-2021-27085	[email protected]	msrc.microsoft.com	Patch, Vendor Advisory
www.cisa.gov/known-exploited-vulnerabilities-catalog	134c704f-9b21-4f2e-91b3-4a467353bcc0	www.cisa.gov	US Government Resource
Security Update Guide - Microsoft Security Response Center	af854a3a-2127-422b-91ae-364da2661108	portal.msrc.microsoft.com	Patch, Vendor Advisory
CVE Program record	CVE.ORG	www.cve.org	canonical
NVD vulnerability detail	NVD	nvd.nist.gov	canonical, analysis
CISA Known Exploited Vulnerabilities catalog	CISA	www.cisa.gov	kev

No vendor comments have been submitted for this CVE.

Additional Advisory Data

Source	Time	Event
ADP	2021-11-03T00:00:00.000Z	CVE-2021-27085 added to CISA KEV

There are currently no legacy QID mappings associated with this CVE.