What is the CVSS score of CVE-2021-41256?

CVE-2021-41256 has a CVSS 3.1 base score of 7.1 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N. EPSS exploitation probability: 1.1%.

Is there a public PoC exploit available for CVE-2021-41256?

Yes, a public proof-of-concept exploit is available for CVE-2021-41256. Prioritise patching immediately. EPSS: 1.1%.

Is there a patch available for CVE-2021-41256?

Yes, a patch is available for CVE-2021-41256. Update the affected software to the latest version immediately.

Nextcloud CVE-2021-41256

HIGH

Inclusion of Functionality from Untrusted Control Sphere (CWE-829)

2021-11-30 security-advisories@github.com

Information Disclosure Google Nextcloud News

7.1

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-829 OWASP Top 10:2025 A08:2025 - Software or Data Integrity Failures ASVS 5.0 V15 - Secure Coding and Architecture Trusted source inclusion only
Impact	CVSS score of 7.1 (HIGH). Attack characteristics: local attack vector, low complexity, no privileges required, user interaction 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 1.1% exploitation probability (EPSS)

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AnalysisAI

nextcloud news-android is an Android client for the Nextcloud news/feed reader app. Rated high severity (CVSS 7.1), this vulnerability is no authentication required, 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

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 under CWE-829. nextcloud news-android is an Android client for the Nextcloud news/feed reader app. In affected versions the Nextcloud News for Android app has a security issue by which a malicious application installed on the same device can send it an arbitrary Intent that gets reflected back, unintentionally giving read and write access to non-exported Content Providers in Nextcloud News for Android. Users should upgrade to version 0.9.9.63 or higher as soon as possible. Affected products include: Nextcloud News. Version information: version 0.9.9.63.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.1 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

DescriptionNVD

nextcloud news-android is an Android client for the Nextcloud news/feed reader app. In affected versions the Nextcloud News for Android app has a security issue by which a malicious application installed on the same device can send it an arbitrary Intent that gets reflected back, unintentionally giving read and write access to non-exported Content Providers in Nextcloud News for Android. Users should upgrade to version 0.9.9.63 or higher as soon as possible.

Threat Intelligence Overview

EPSS Score

1.1%

Top 39% exploitable

Exploit

POC

Public exploit code exists

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

GitHub

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 1.1%

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: +36

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.