What is the CVSS score of CVE-2026-21427?

CVE-2026-21427 has a CVSS 3.0 base score of 7.8 (High). CVSS vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

How to fix or mitigate CVE-2026-21427?

Within 7 days: Identify all affected systems and apply vendor patches promptly. Monitor vendor channels for patch availability.

CVE-2026-21427

HIGH

Uncontrolled Search Path Element (CWE-427)

2026-01-08 vultures@jpcert.or.jp

Privilege Escalation RCE

7.8

CVSS 3.0 · NVD

View

Attack ChainAIDerived

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

Access

Place malicious DLL in directory
Delivery

User executes Pioneer installer
Exploit

Installer searches insecure DLL path
Execution

Load attacker-controlled DLL
Impact

Execute arbitrary code with installer privileges

Vulnerability Assessment

Weakness	CWE CWE-427 OWASP Top 10:2025 A08:2025 - Software or Data Integrity Failures ASVS 5.0 V13 - Configuration Search path element control
Exploitation Conditions	Pioneer product installer must be executed by user in directory containing attacker-controlled DLL file matching expected DLL name. Requires local file system access and user interaction to launch installer.
Impact	CVSS 7.8 (HIGH). Attack vector: Local. Complexity: Low. Privileges required: None. User interaction: Required.
Exploit ScenarioDerived	An attacker could exploit this vulnerability to insecurely loading Dynamic Link Libraries.

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

No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Arbitrary code execution in PIONEER CORPORATION product installers through DLL search path manipulation allows local attackers with user interaction to execute malicious code with installer privileges. The vulnerability affects multiple products and requires user interaction to trigger, potentially compromising system integrity during software installation. No patch is currently available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 7.8

The installers for multiple products provided by PIONEER CORPORATION contain an issue with the DLL search path, which may lead to insecurely loading Dynamic Link Libraries. As a result, arbitrary code may be executed with the privileges of the running installer. [CVSS 7.8 HIGH]

RemediationAI

Monitor vendor advisories for a patch.

Affected ProductsAI

The installers for multiple products provided by PIONEER CORPORATION contain an issue with the DLL search path, which may lead to insecurely loading D

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

Classified as CWE-427 (Uncontrolled Search Path Element). The installers for multiple products provided by PIONEER CORPORATION contain an issue with the DLL search path, which may lead to insecurely loading Dynamic Link Libraries. As a result, arbitrary code may be executed with the privileges of the running installer.

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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:N/UI:R/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

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

Executive ViewAI

Why It Matters

Organizations using installers for multiple products provided by PIONEER CORPORATION contain an face notable risk from CVE-2026-21427, a DLL hijacking vulnerability rated CVSS 7.8. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: High

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score

0.0%

Top 100% 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 HIGH

CISA KEV No

Public POC No

EPSS 0.0%

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

Small

Automatable· derived

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +39

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.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.