What is the CVSS score of CVE-2026-20418?

CVE-2026-20418 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

How to fix or mitigate CVE-2026-20418?

Within 24 hours: Identify and inventory all systems running Thread; assess exposure in production and non-production environments; establish incident response readiness. Within 7 days: Implement network segmentation to isolate Thread services; enable enhanced monitoring and logging for Thread processes; establish vendor communication channels for patch timeline. Within 30 days: Deploy compensating controls (WAF rules, input validation hardening, or service isolation); conduct penetration testing of affected systems; develop and test rollback procedures for Thread upgrades when patches become available.

Matter CVE-2026-20418

CRITICAL

Out-of-bounds Write (CWE-787)

2026-02-02 security@mediatek.com

Privilege Escalation Google Matter

9.8

CVSS 3.1 · NVD

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Send malicious network packet to Thread service
Exploit

Trigger out of bounds write via missing bounds check
Execution

Escalate privileges to system level
Impact

Execute arbitrary code with elevated access

Vulnerability Assessment

Weakness	CWE CWE-787 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, write limits MITRE ATT&CK 2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	No special conditions — remote unauthenticated exploitation against Thread service with default configuration allowing network access without authentication or user interaction.
Impact	CVSS 9.8. Thread is an IoT mesh networking protocol — remote exploitation affects smart home devices.
Exploit ScenarioDerived	Attacker on the Thread mesh network sends crafted packets causing OOB write, achieving remote code execution on the Android device.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Remote privilege escalation in Android Thread networking protocol implementation via out-of-bounds write. No additional execution privileges needed.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 22:01 CVSS 9.8

Remote code execution in Android Thread protocol.

RemediationAI

Apply Android security update.

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

CWE-787 OOB write in Thread networking stack. Remote exploitation without authentication or privileges.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL

AV:N/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

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

In Thread, there is a possible out of bounds write due to a missing bounds check. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: WCNCR00465153; Issue ID: MSV-4927.

Executive ViewAI

Why It Matters

CVE-2026-20418 is a critical remote privilege escalation vulnerability affecting Thread with a 9.8 CVSS score and no available patch. Attackers can exploit this flaw to gain unauthorized administrative access to affected systems without requiring special permissions, potentially compromising sensitive data and operational integrity across the organization.

Business Impact: Severe

Compensating Controls

Until patch availability: Implement strict network segmentation isolating Thread services; deploy Web Application Firewall (WAF) rules blocking suspicious input patterns targeting Thread; disable non-essential Thread features and services; enforce strict access controls limiting Thread service exposure; implement robust logging and real-time alerting for Thread processes; consider temporary service shutdown if business continuity allows; apply strict input validation and bounds checking at application layer where possible.

Threat Intelligence Overview

EPSS Score

0.1%

Top 81% exploitable

Data Quality

3 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 CRITICAL

CISA KEV No

Public POC No

EPSS 0.1%

Patch available No

Active threat No

Deciding rule

CRITICAL severity

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

Out-of-Cycle

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Very High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +49

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Privilege Escalation HIGH

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.