PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-54309 n8n-io CVE debrief

The n8n workflow automation platform has a high-severity vulnerability, CVE-2026-54309, with a CVSS score of 8.8. The vulnerability exists in the @n8n/mcp-browser component when run in HTTP transport mode, allowing unauthenticated access to browser-control capabilities. This could enable an attacker to navigate, evaluate JavaScript, and access cookies and storage against the user's real browser profile. The vulnerability affects instances where @n8n/mcp-browser is run with the HTTP transport (--transport http).

Vendor
n8n-io
Product
n8n
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-23
Original CVE updated
2026-06-25
Advisory published
2026-06-23
Advisory updated
2026-06-25

Who should care

Security teams and administrators responsible for n8n workflow automation platforms should be aware of this vulnerability. If the @n8n/mcp-browser component is used in HTTP transport mode, immediate action is necessary to prevent exploitation. Users of the n8n AI Browser Bridge extension should also take precautions to ensure their browser connections are secure.

Technical summary

CVE-2026-54309 is a high-severity vulnerability in the n8n workflow automation platform. The @n8n/mcp-browser component, when run in HTTP transport mode, accepts session initialization and tool invocation requests without authentication. This allows any network-reachable client or visited website to establish an MCP session and invoke browser-control tools. If the n8n AI Browser Bridge extension is installed and a browser connection is active, an unauthenticated caller can access browser-control capabilities. The vulnerability is fixed in versions 2.25.7 and 2.26.2.

Defensive priority

High priority should be given to updating the n8n workflow automation platform to versions 2.25.7 or 2.26.2. Instances where @n8n/mcp-browser is run with the HTTP transport (--transport http) should be immediately patched to prevent exploitation.

Recommended defensive actions

  • Update n8n to version 2.25.7 or 2.26.2
  • Disable HTTP transport mode for @n8n/mcp-browser
  • Verify and restrict access to browser-control capabilities
  • Monitor for suspicious activity on n8n instances
  • Review and update compensating controls for n8n workflow automation platforms

Evidence notes

The CVE-2026-54309 vulnerability was published on June 23, 2026, and modified on June 25, 2026. The vulnerability affects n8n workflow automation platforms using @n8n/mcp-browser in HTTP transport mode. Evidence from the NVD and CVE.org confirms the vulnerability's existence and provides details on affected versions.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-54309 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-54309

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-54309 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-54309

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.