CVE-2026-54309: CWE-306: Missing Authentication for Critical Function in n8n-io n8n
n8n is an open source workflow automation platform. Prior to 2.25.7 and 2.26.2, when @n8n/mcp-browser is run in HTTP transport mode, the MCP endpoint accepts session initialization and tool invocation requests without any authentication. Any network-reachable client, or any website visited by the user, can establish an MCP session and invoke browser-control tools. Where the n8n AI Browser Bridge extension is installed and a browser connection is active, an unauthenticated caller can access browser-control capabilities including navigation, JavaScript evaluation, and cookie and storage access against the user's real browser profile. This issue only affects instances where @n8n/mcp-browser is run with the HTTP transport (--transport http). This vulnerability is fixed in 2.25.7 and 2.26.2.
AI Analysis
Technical Summary
The vulnerability CVE-2026-54309 in n8n-io n8n arises from missing authentication on the MCP endpoint when @n8n/mcp-browser is run with HTTP transport (--transport http). This allows unauthenticated network clients or websites to initiate MCP sessions and invoke browser-control functions. When the AI Browser Bridge extension is active, attackers can perform browser navigation, JavaScript evaluation, and access cookies and storage tied to the user's real browser profile. This issue affects versions prior to 2.25.7 and 2.26.2 and is resolved in those fixed versions.
Potential Impact
An unauthenticated attacker can remotely control browser functions including navigation, script execution, and access to sensitive browser data such as cookies and storage. This compromises user privacy and security by allowing unauthorized access to the user's real browser profile and potentially sensitive information stored therein.
Mitigation Recommendations
This vulnerability is fixed in n8n versions 2.25.7 and 2.26.2. Users should upgrade to at least these versions to remediate the issue. Until upgraded, avoid running @n8n/mcp-browser with HTTP transport mode enabled. Patch status is not explicitly confirmed beyond the fixed versions; check vendor advisories for current remediation guidance.
CVE-2026-54309: CWE-306: Missing Authentication for Critical Function in n8n-io n8n
Description
n8n is an open source workflow automation platform. Prior to 2.25.7 and 2.26.2, when @n8n/mcp-browser is run in HTTP transport mode, the MCP endpoint accepts session initialization and tool invocation requests without any authentication. Any network-reachable client, or any website visited by the user, can establish an MCP session and invoke browser-control tools. Where the n8n AI Browser Bridge extension is installed and a browser connection is active, an unauthenticated caller can access browser-control capabilities including navigation, JavaScript evaluation, and cookie and storage access against the user's real browser profile. This issue only affects instances where @n8n/mcp-browser is run with the HTTP transport (--transport http). This vulnerability is fixed in 2.25.7 and 2.26.2.
CVSS v4.0
Score 8.8high
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-54309 in n8n-io n8n arises from missing authentication on the MCP endpoint when @n8n/mcp-browser is run with HTTP transport (--transport http). This allows unauthenticated network clients or websites to initiate MCP sessions and invoke browser-control functions. When the AI Browser Bridge extension is active, attackers can perform browser navigation, JavaScript evaluation, and access cookies and storage tied to the user's real browser profile. This issue affects versions prior to 2.25.7 and 2.26.2 and is resolved in those fixed versions.
Potential Impact
An unauthenticated attacker can remotely control browser functions including navigation, script execution, and access to sensitive browser data such as cookies and storage. This compromises user privacy and security by allowing unauthorized access to the user's real browser profile and potentially sensitive information stored therein.
Mitigation Recommendations
This vulnerability is fixed in n8n versions 2.25.7 and 2.26.2. Users should upgrade to at least these versions to remediate the issue. Until upgraded, avoid running @n8n/mcp-browser with HTTP transport mode enabled. Patch status is not explicitly confirmed beyond the fixed versions; check vendor advisories for current remediation guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-12T18:42:02.222Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3aafb0eed863c81e44dd57
Added to database: 06/23/2026, 16:09:20 UTC
Last enriched: 06/23/2026, 16:24:19 UTC
Last updated: 06/23/2026, 23:20:07 UTC
Views: 5
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.