CVE-2026-123139
Received Received - Intake

Improper Origin Validation in Opera Neon MCP Hub Extension

Publication date: 2026-11-12

Last updated on: 2026-11-12

Assigner: Opera

Description
Improper verification of the source of a communication channel vulnerability in Opera Neon on macOS and Windows allows a malicious browser extension to take control of the browser by sending commands through MCP Hub to the built-in Browser Operator extension. This issue affects Opera Neon MCP Hub extension: 0.0.1.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-11-12
Last Modified
2026-11-12
Generated
2026-11-12
AI Q&A
2026-11-12
EPSS Evaluated
N/A
NVD
CVE-2026-123139
EUVD
EUVD-2026-124370

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
Opera Neon 1.0.0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-940 The product establishes a communication channel to handle an incoming request that has been initiated by an actor, but it does not properly verify that the request is coming from the expected origin.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability involves improper verification of the source of a communication channel in Opera Neon on macOS and Windows. A malicious browser extension can exploit this to send commands through the MCP Hub to the built-in Browser Operator extension, allowing it to take control of the browser.

Detection Guidance

Check installed Opera Neon MCP Hub extensions for version 0.0.1. Inspect browser extension permissions and network traffic for unauthorized MCP Hub communications.

Impact Analysis

A malicious browser extension could gain control of your Opera Neon browser, potentially allowing it to execute unauthorized actions, access sensitive data, or perform actions on your behalf without your knowledge.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR or HIPAA as it involves a browser extension exploit rather than data handling or privacy violations. However, if exploited, it could lead to unauthorized access to sensitive data, potentially impacting compliance indirectly.

Mitigation Strategies

Update or remove the Opera Neon MCP Hub extension version 0.0.1. Disable untrusted browser extensions. Monitor browser activity for suspicious commands.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-123139. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart

Security Radar

News mentioning this vulnerability
Loading related security news...