What is the CVSS score of CVE-2020-8236?

CVE-2020-8236 has a CVSS 3.1 base score of 6.8 (Medium). CVSS vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.6%.

Is there a public PoC exploit available for CVE-2020-8236?

Yes, a public proof-of-concept exploit is available for CVE-2020-8236. Prioritise patching immediately. EPSS: 0.6%.

Nextcloud Server CVE-2020-8236

MEDIUM

Improper Authentication (CWE-287)

2020-11-02 support@hackerone.com

Authentication Bypass Nextcloud Server Nextcloud

6.8

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 6.8 (MEDIUM). Attack characteristics: physical attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	An attacker could exploit this vulnerability to bypass authentication mechanisms to gain unauthorized access. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

No patch listed yet 0.6% exploitation probability (EPSS)

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AnalysisAI

A wrong configuration in Nextcloud Server 19.0.1 incorrectly made the user feel the passwordless WebAuthn is also a two factor verification by asking for the PIN of the passwordless WebAuthn but not. Rated medium severity (CVSS 6.8), this vulnerability is no authentication required, low attack complexity. Public exploit code available and 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. A wrong configuration in Nextcloud Server 19.0.1 incorrectly made the user feel the passwordless WebAuthn is also a two factor verification by asking for the PIN of the passwordless WebAuthn but not verifying it. Affected products include: Nextcloud Nextcloud Server.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.8 MEDIUM

AV:P/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

Physical

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

Threat Intelligence Overview

EPSS Score

0.6%

Top 56% 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 MEDIUM

CISA KEV No

Public POC Yes

EPSS 0.6%

Patch available No

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

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: +34

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:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*

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Same weakness CWE-287 – Improper Authentication

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References

Advisories & patches

ADVISORY https://nextcloud.com/security/advisory/?id=NC-SA-2020-037

Search Externally

GitHub PoC

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