What is the CVSS score of CVE-2021-35979?

CVE-2021-35979 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%.

Realport CVE-2021-35979

HIGH

Missing Authentication for Critical Function (CWE-306)

2021-10-08 cve@mitre.org

Authentication Bypass Realport Connectport Ts 8 16 Firmware Connectport Lts 8 16 32 Firmware Passport Integrated Console Server Firmware Cm Firmware Portserver Ts Firmware Portserver Ts Mei Firmware Portserver Ts Mei Hardened Firmware Portserver Ts M Mei Firmware 6350 Sr Firmware Portserver Ts P Mei Firmware Transport Wr11 Xt Firmware One Iap Family Firmware One Ia Firmware Wr31 Firmware Wr44 R Firmware Connect Es Firmware Wr21 Firmware Digi

8.1

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-306 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V6 - Authentication Authentication required for critical functions MITRE ATT&CK 1 technique across 1 tactic: 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 access critical functionality without authentication 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

An issue was discovered in Digi RealPort through 4.8.488.0. 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. Require authentication for all sensitive operations, implement defense in depth.

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 Missing Authentication for Critical Function (CWE-306), which allows attackers to access critical functionality without authentication. An issue was discovered in Digi RealPort through 4.8.488.0. The 'encrypted' mode is vulnerable to man-in-the-middle attacks and does not perform authentication. Affected products include: Digi Realport, Digi Connectport Ts 8\/16 Firmware, Digi Connectport Lts 8\/16\/32 Firmware, Digi Passport Integrated Console Server Firmware, Digi Cm Firmware. Version information: through 4.8.488.0..

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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

An issue was discovered in Digi RealPort through 4.8.488.0. The 'encrypted' mode is vulnerable to man-in-the-middle attacks and does not perform authentication.

Threat Intelligence Overview

EPSS Score

0.9%

Top 46% 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.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +40

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)NVD

cpe:2.3:a:digi:realport:*:*:*:*:*:linux:*:*

cpe:2.3:a:digi:realport:*:*:*:*:*:windows:*:*

cpe:2.3:o:digi:connectport_ts_8\/16_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:connectport_lts_8\/16\/32_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:passport_integrated_console_server_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:cm_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:portserver_ts_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:portserver_ts_mei_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:portserver_ts_mei_hardened_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:portserver_ts_m_mei_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:6350-sr_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:portserver_ts_p_mei_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:transport_wr11_xt_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:one_iap_family_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:one_ia_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:wr31_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:wr44_r_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:connect_es_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:digi:wr21_firmware:*:*:*:*:*:*:*:*

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References

Advisories & patches

REF https://raw.githubusercontent.com/reidmefirst/vuln-disclosure/main/2021-02.txt

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