What is the CVSS score of CVE-2021-40454?

CVE-2021-40454 has a CVSS 3.1 base score of 5.5 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.5%.

Is there a patch available for CVE-2021-40454?

Yes, a patch is available for CVE-2021-40454. Update the affected software to the latest version immediately.

365 Apps CVE-2021-40454

MEDIUM

Cleartext Storage of Sensitive Information (CWE-312)

2021-10-13 secure@microsoft.com

Information Disclosure Microsoft 365 Apps Office Windows Server 2012 Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows 10 Windows 8 1 Windows Rt 8 1 Windows Server Windows 11

5.5

CVSS 3.1 · Vendor: microsoft

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Vulnerability Assessment

Weakness	CWE CWE-312 OWASP Top 10:2025 A06:2025 - Insecure Design ASVS 5.0 V14 - Data Protection Encrypted storage of sensitive data
Impact	CVSS score of 5.5 (MEDIUM). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required.
Exploit ScenarioDerived	Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 0.5% exploitation probability (EPSS)

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AnalysisAI

Rich Text Edit Control Information Disclosure Vulnerability. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

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Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-312. Affected products include: Microsoft 365 Apps, Microsoft Office, Microsoft Windows 10, Microsoft Windows 11, Microsoft Windows 8.1.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 5.5 MEDIUM

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

Primary rating from Vendor (microsoft) · only source for this CVE.

CVSS VectorVendor: microsoft

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

DescriptionCVE.org

Rich Text Edit Control Information Disclosure Vulnerability

Threat Intelligence Overview

EPSS Score

0.5%

Top 61% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 0.5%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Defer

Exploitation· derived

None

System Exposure· derived

Small

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +28

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)CVE.org

cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*

cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*

cpe:2.3:a:microsoft:office:2013:sp1:*:*:*:*:x64:*

cpe:2.3:a:microsoft:office:2013:sp1:*:*:*:*:x86:*

cpe:2.3:a:microsoft:office:2013_rt:sp1:*:*:*:*:*:*

cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:x64:*

cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:x86:*

cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x64:*

cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:x86:*

cpe:2.3:a:microsoft:office:2019:*:*:*:*:macos:*:*

cpe:2.3:a:microsoft:office:2021:*:ltsc:*:*:macos:*:*

cpe:2.3:a:microsoft:office:2021:*:ltsc:*:*:x64:*:*

cpe:2.3:a:microsoft:office:2021:*:ltsc:*:*:x86:*:*

cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:x64:*

cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:x86:*

cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:arm64:*

cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:x64:*

cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:x86:*

cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:arm64:*

cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:x64:*

+ 24 more

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Same weakness CWE-312 – Cleartext Storage of Sensitive Information

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References

Advisories & patches

PATCH https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40454

Search Externally

GitHub PoC

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