What is the CVSS score of CVE-2023-3127?

CVE-2023-3127 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.6%.

Istar Ultra Firmware CVE-2023-3127

CRITICAL

Improper Authentication (CWE-287)

2023-07-11 productsecurity@jci.com

Authentication Bypass Istar Ultra Firmware Istar Ultra Lt Firmware Istar Ultra G2 Firmware Edge G2 Firmware Johnsoncontrols

9.8

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-287 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V6 - Authentication Authentication mechanism validation MITRE ATT&CK 2 techniques across 2 tactics: Defense Evasion, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.
Exploit ScenarioDerived	A remote attacker could bypass authentication mechanisms to gain unauthorized access by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

No patch listed yet 0.6% exploitation probability (EPSS)

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AnalysisAI

An unauthenticated user could log into iSTAR Ultra, iSTAR Ultra LT, iSTAR Ultra G2, and iSTAR Edge G2 with administrator rights. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Implement multi-factor authentication, enforce strong password policies, use proven authentication frameworks.

Affects your stack

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

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 as Improper Authentication (CWE-287), which allows attackers to bypass authentication mechanisms to gain unauthorized access. An unauthenticated user could log into iSTAR Ultra, iSTAR Ultra LT, iSTAR Ultra G2, and iSTAR Edge G2 with administrator rights. Affected products include: Johnsoncontrols Istar Ultra Firmware, Johnsoncontrols Istar Ultra Lt Firmware, Johnsoncontrols Istar Ultra G2 Firmware, Johnsoncontrols Edge G2 Firmware.

Severity by source

NVD PRIMARY 9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

An unauthenticated user could log into iSTAR Ultra, iSTAR Ultra LT, iSTAR Ultra G2, and iSTAR Edge G2 with administrator rights.

Threat Intelligence Overview

EPSS Score

0.6%

Top 57% 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 CRITICAL

CISA KEV No

Public POC No

EPSS 0.6%

Patch available No

Active threat No

Deciding rule

CRITICAL severity

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.