What is the CVSS score of CVE-2021-33895?

CVE-2021-33895 has a CVSS 3.1 base score of 8.1 (High). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.9%.

Backbox H4 09 Firmware CVE-2021-33895

HIGH

Improper Authentication (CWE-287)

2021-06-25 cve@mitre.org

Authentication Bypass Backbox H4 09 Firmware Backbox E4 09 Firmware Hpe

8.1

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 8.1 (HIGH). Attack characteristics: network attack vector, high 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.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.9% exploitation probability (EPSS)

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AnalysisAI

ETINET BACKBOX E4.09 and H4.09 mismanages password access control. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. 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. ETINET BACKBOX E4.09 and H4.09 mismanages password access control. When a user uses the User ID of the process running BBSV to login to the Backbox UI application, the system procedure (USER_AUTHENTICATE_) used for verifying the Password returns 0 (no error). The reason is that the user is not running the XYGate application. Hence, BBSV assumes the Password is correct. For H4.09, the affected version isT0954V04^AAO. For E4.09, the affected version is 22SEP2020. Note: If your current version is E4.10-16MAY2021 (version procedure T9999V04_16MAY2022_BPAKETI_10), a hotfix (FIXPAK-19OCT-2022) is available in version E4.10-19OCT2022. Resolution to CVE-2021-33895 in version E4.11-19OCT2022 Affected products include: Hpe Backbox H4.09 Firmware, Etinet Backbox E4.09 Firmware.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 8.1 HIGH

AV:N/AC:H/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

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

ETINET BACKBOX E4.09 and H4.09 mismanages password access control. When a user uses the User ID of the process running BBSV to login to the Backbox UI application, the system procedure (USER_AUTHENTICATE_) used for verifying the Password returns 0 (no error). The reason is that the user is not running the XYGate application. Hence, BBSV assumes the Password is correct. For H4.09, the affected version isT0954V04^AAO. For E4.09, the affected version is 22SEP2020. Note: If your current version is E4.10-16MAY2021 (version procedure T9999V04_16MAY2022_BPAKETI_10), a hotfix (FIXPAK-19OCT-2022) is available in version E4.10-19OCT2022. Resolution to CVE-2021-33895 in version E4.11-19OCT2022

Threat Intelligence Overview

EPSS Score

0.9%

Top 44% 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 HIGH

CISA KEV No

Public POC No

EPSS 0.9%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

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.