CVE-2026-123139

high

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.

References

https://security.opera.com/en/improper-verification-of-source-of-a-communication-channel-opera-security-advisories/

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-124370

Details

Source: Mitre, NVD

Published: 2026-11-12

Updated: 2026-11-12

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 8.4

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N

Severity: High

EPSS

EPSS: 0.00121