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Vulnerabilities/CVE-2021-27085
Vulnerability dossier

CVE-2021-27085

VendormicrosoftPublishedMar 11, 2021SourceNVD
Act now

Actively exploited in the wild. Patch or mitigate immediately — don't wait for a maintenance window.

Severity
High · 8.8
CVSS base score
Exploitation
In the wild
CISA KEV
Predicted risk
5% model
EPSS forecast — overtaken by confirmed exploitation
Exposure
Remote
Exploitable over the network without credentials
01

What's the risk?

An unauthenticated attacker, remotely over the network, if a user is tricked into opening a malicious file or link, can tamper with data.

Internet Explorer Remote Code Execution Vulnerability

How it's exploitedMITRE ATT&CK · inferred from weakness & vector
Execution
T1203Exploitation for Client Execution

Inferred from the weakness type (CWE) and how the flaw is reached — the techniques an attacker would chain to exploit this. Real-world corroboration appears here as threat intel is folded in.

02

Who's exploiting it?

Corroborated threat activity referencing this CVE — with source and confidence, not inference.

Confirmed exploited in the wild. CISA KEV · catalogued Nov 3, 2021

Named threat actors and observed ATT&CK techniques appear here as intel feeds are folded in — the ATT&CK chain above stays inferred until then.

03

Are we affected?

1
  • Affectedmicrosoft · internet_explorer11
04

What to do

Generated by Wavense from the CVE record — an immediate mitigation and the permanent fix.

  1. !

    Mitigate now

    Until patches are applied, organizations should configure Group Policies to disable Internet Explorer scripting or enforce "Enterprise Mode" to restrict functionality. Implement strict network segmentation and egress filtering to limit potential command-and-control communications from compromised machines. Additionally, educate users to avoid opening untrusted web links and emails, and deploy endpoint detection and response (EDR) solutions for enhanced monitoring.

  2. ✓

    Permanent fix

    The permanent resolution involves applying the latest security updates released by Microsoft for affected Internet Explorer versions through Windows Update. These updates address the underlying vulnerability, preventing remote code execution exploits. For environments where Internet Explorer is no longer required, consider disabling or uninstalling it, or transitioning to modern, supported browsers for all web-based activities.

Technical details— weakness, CVSS vector & calculator, related CVEs

Business impact

An attacker could exploit this vulnerability to achieve arbitrary code execution on the victim's system with the same privileges as the logged-on user. This allows for complete compromise of the affected machine, potentially leading to data theft, installation of malware, or further lateral movement within the network, causing significant business disruption and reputational damage.

Weakness

No CWE classification has been assigned.

CVSS 3.1 details

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L
0.0
/ 10.0 base
High severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L
Exploitability metrics
Attack VectorAV
Remotely exploitable across a network
Attack ComplexityAC
No special conditions required
Privileges RequiredPR
No authorization needed
User InteractionUI
A user must take an action
Impact metrics
ScopeS
Impact extends to other components
ConfidentialityC
Limited disclosure
IntegrityI
Total loss of integrity
AvailabilityA
Reduced performance or interruptions

Related vulnerabilities

Other CVEs affecting internet explorer

NVD
9.8Critical
CVE-2015-0313KEV⚙ WeaponizedExploit likely

Use-after-free vulnerability in Adobe Flash Player before 13.0.0.269 and 14.x through 16.x before 16.0.0.305 on Windows and OS X and before 11.2.202.442 on Linux allows remote attackers to execute arbitrary code via unspecified vectors, as exploited in the wild in February 2015, a different vulnerability than CVE-2015-0315, CVE-2015-0320, and CVE-2015-0322.

adobeCWE-416Use After FreeNetworkLow effortNo authNo interactionCIA
2015-02-02
NVD
9.8Critical
CVE-2015-0311KEV⚙ WeaponizedExploit likely

Unspecified vulnerability in Adobe Flash Player through 13.0.0.262 and 14.x, 15.x, and 16.x through 16.0.0.287 on Windows and OS X and through 11.2.202.438 on Linux allows remote attackers to execute arbitrary code via unknown vectors, as exploited in the wild in January 2015.

adobeNetworkLow effortNo authNo interactionCIA
2015-01-23
NVD
9.8Critical
CVE-2014-1776KEVExploit likely

Use-after-free vulnerability in Microsoft Internet Explorer 6 through 11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via vectors related to the CMarkup::IsConnectedToPrimaryMarkup function, as exploited in the wild in April 2014. NOTE: this issue originally emphasized VGX.DLL, but Microsoft clarified that "VGX.DLL does not contain the vulnerable code leveraged in this exploit. Disabling VGX.DLL is an exploit-specific workaround that provides an immediate, effective workaround to help block known attacks."

microsoftCWE-416Use After FreeNetworkLow effortNo authNo interactionCIA
2014-04-27
NVD
8.8High
CVE-2021-26411KEVExploit likely

Internet Explorer Memory Corruption Vulnerability

microsoftCWE-416Use After FreeNetworkLow effortNo authUser neededCIA
2021-03-11
NVD
8.8High
CVE-2019-0541KEVPoCExploit likely

A remote code execution vulnerability exists in the way that the MSHTML engine inproperly validates input, aka "MSHTML Engine Remote Code Execution Vulnerability." This affects Microsoft Office, Microsoft Office Word Viewer, Internet Explorer 9, Internet Explorer 11, Microsoft Excel Viewer, Internet Explorer 10, Office 365 ProPlus.

microsoftCWE-77Command InjectionNetworkLow effortNo authUser neededCIA
2019-01-08
NVD
8.8High
CVE-2017-0222KEV

A remote code execution vulnerability exists when Internet Explorer improperly accesses objects in memory, aka "Internet Explorer Memory Corruption Vulnerability." This CVE ID is unique from CVE-2017-0226.

microsoftCWE-787Out-of-bounds WriteNetworkLow effortNo authUser neededCIA
2017-05-12
NVD
8.8High
CVE-2017-0210KEV

An elevation of privilege vulnerability exists when Internet Explorer does not properly enforce cross-domain policies, which could allow an attacker to access information from one domain and inject it into another domain, aka "Internet Explorer Elevation of Privilege Vulnerability."

microsoftNetworkLow effortNo authUser neededCIA
2017-04-12
NVD
8.8High
CVE-2017-0149KEV

Microsoft Internet Explorer 9 through 11 allow remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "Internet Explorer Memory Corruption Vulnerability." This vulnerability is different from those described in CVE-2017-0018 and CVE-2017-0037.

microsoftCWE-787Out-of-bounds WriteNetworkLow effortNo authUser neededCIA
2017-03-16
0.0
/ 10.0 base
High severity
Key facts
CVE ID
CVE-2021-27085
Published
Mar 11, 2021
Last modified
Aug 19, 2026
CVSS
8.8 (v3.1)
EPSS
5.45%
In CISA KEV
Yes
Confidence
98/100
Timeline
  1. Mar 11, 2021Published to NVDNVD
  2. Aug 19, 2026Record last modifiedNVD
  3. Aug 19, 2026AI analysis generatedWavense
View on NVD