What is the CVSS score of CVE-2021-20607?

CVE-2021-20607 has a CVSS 3.1 base score of 5.5 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.9%.

Is there a patch available for CVE-2021-20607?

Yes, a patch is available for CVE-2021-20607. Update the affected software to the latest version immediately.

Gx Works2 CVE-2021-20607

MEDIUM

Integer Underflow (CWE-191)

2021-12-17 Mitsubishielectric.Psirt@yd.MitsubishiElectric.co.jp

Information Disclosure Integer Overflow Gx Works2 Melsoft Navigator Ezsocket Mitsubishielectric

5.5

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-191 ASVS 5.0 V15 - Secure Coding and Architecture Integer underflow checks
Impact	CVSS score of 5.5 (MEDIUM). Attack characteristics: local attack vector, low complexity, no privileges required, user interaction 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 0.9% exploitation probability (EPSS)

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AnalysisAI

Integer Underflow vulnerability in Mitsubishi Electric GX Works2 versions 1.606G and prior, Mitsubishi Electric MELSOFT Navigator versions 2.84N and prior and Mitsubishi Electric EZSocket versions. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, 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

Find out whether the stacks and servers you run are on an affected version.

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Technical ContextAI · show details

This vulnerability is classified under CWE-191. Integer Underflow vulnerability in Mitsubishi Electric GX Works2 versions 1.606G and prior, Mitsubishi Electric MELSOFT Navigator versions 2.84N and prior and Mitsubishi Electric EZSocket versions 5.4 and prior allows an attacker to cause a DoS condition in the software by getting a user to open malicious project file specially crafted by an attacker. Affected products include: Mitsubishielectric Ezsocket, Mitsubishielectric Gx Works2, Mitsubishielectric Melsoft Navigator.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.5 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

DescriptionNVD

Integer Underflow vulnerability in Mitsubishi Electric GX Works2 versions 1.606G and prior, Mitsubishi Electric MELSOFT Navigator versions 2.84N and prior and Mitsubishi Electric EZSocket versions 5.4 and prior allows an attacker to cause a DoS condition in the software by getting a user to open malicious project file specially crafted by an attacker.

Threat Intelligence Overview

EPSS Score

0.9%

Top 43% 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 0.9%

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: +1

CVSS: +28

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Integer Overflow MEDIUM

Integer overflow occurs when an arithmetic operation produces a result that exceeds the maximum value a given integer type can store.

Information Disclosure MEDIUM

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