What is the CVSS score of CVE-2023-27516?

CVE-2023-27516 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.5%.

Is there a public PoC exploit available for CVE-2023-27516?

Yes, a public proof-of-concept exploit is available for CVE-2023-27516. Prioritise patching immediately. EPSS: 0.5%.

Is there a patch available for CVE-2023-27516?

Yes, a patch is available for CVE-2023-27516. Update the affected software to the latest version immediately.

Vpn CVE-2023-27516

HIGH

Insecure Default Variable Initialization (CWE-453)

2023-10-12 talos-cna@cisco.com

Authentication Bypass Vpn Softether

7.8

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-453
Impact	CVSS score of 7.8 (HIGH). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	Successful exploitation could compromise the high-severity affected system.

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

Patch available 0.5% exploitation probability (EPSS)

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AnalysisAI

An authentication bypass vulnerability exists in the CiRpcAccepted() functionality of SoftEther VPN 4.41-9782-beta and 5.01.9674. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available.

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-453. An authentication bypass vulnerability exists in the CiRpcAccepted() functionality of SoftEther VPN 4.41-9782-beta and 5.01.9674. A specially crafted network packet can lead to unauthorized access. An attacker can send a network request to trigger this vulnerability. Affected products include: Softether Vpn.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.8 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

An authentication bypass vulnerability exists in the CiRpcAccepted() functionality of SoftEther VPN 4.41-9782-beta and 5.01.9674. A specially crafted network packet can lead to unauthorized access. An attacker can send a network request to trigger this vulnerability.

Threat Intelligence Overview

EPSS Score

0.5%

Top 59% exploitable

Exploit

POC

Public exploit code exists

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 Yes

EPSS 0.5%

Patch available Yes

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

Poc

System Exposure· derived

Small

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +39

PoC: +20

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:softether:vpn:4.41-9782:beta:*:*:*:*:*:*

cpe:2.3:a:softether:vpn:5.01.9674:*:*:*:*:*:*:*

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Same weakness CWE-453 – Insecure Default Variable Initialization

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References

Advisories & patches

PATCH https://www.softether.org/9-about/News/904-SEVPN202301 REF https://www.talosintelligence.com/vulnerability_reports/TALOS-2023-1754

Search Externally

GitHub PoC

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