CVE-2026-123139
Opera Neon MCP Hub Improper Source Verification Vulnerability
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.
INFO
Published Date :
Nov. 12, 2026, 12:22 p.m.
Last Modified :
Nov. 12, 2026, 12:22 p.m.
Remotely Exploit :
No
Source :
Opera
Affected Products
The following products are affected by CVE-2026-123139
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 9aee7086-24f5-48b4-9428-908ac90b8b54 |
Solution
- Update Opera Neon to the latest version.
- Disable or remove malicious browser extensions.
- Review communication channel security settings.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-123139 vulnerability anywhere in the article.