How severe is CVE-2026-54309?

No CVSS score has been assigned to CVE-2026-54309 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-54309?

CVE-2026-54309 affects the following packages: n8n (npm), n8n (npm). Ecosystems affected: npm.

How do I fix CVE-2026-54309?

Update n8n to 2.26.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54309 is resolved across your whole dependency graph.

How do I detect CVE-2026-54309 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for n8n, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-54309 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-54309?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-54309 can be triaged on real exposure rather than presence alone.

Is CVE-2026-54309 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-54309 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-54309?

CVE-2026-54309 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 43th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-54309?

CVE-2026-54309 is classified as Missing Authentication (CWE-306). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-54309 published, and has it been updated?

CVE-2026-54309 was published on June 23, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-54309 — n8n

CVE-2026-54309 is a Missing Authentication vulnerability in n8n. A fix is available for n8n — see the affected versions and patch details below.

n8n: n8n MCP Browser HTTP Transport Exposes Unauthenticated Browser-Control Sessions

Also known asGHSA-qrx8-25qr-5r7v

Published

Jun 23, 2026

Updated

Aug 12, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs43th percentile — riskier than 43% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

37other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

n8nnpm

71Kdownloads / week

Description

Impact

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). The default transport is stdio, which is not affected.

Patches

The issue has been fixed in n8n versions 2.25.7, and 2.26.2. Users should upgrade to one of these versions or later to remediate the vulnerability.

Workarounds

If upgrading is not immediately possible, administrators should consider the following temporary mitigations:

Avoid running @n8n/mcp-browser with the HTTP transport; use the default stdio transport instead.
If HTTP transport is required, restrict network access to the listening port to trusted clients only using host-based firewall rules.

These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`n8n`	≥ 2.26.0&&< 2.26.2	2.26.2`npm install n8n@2.26.2`
📦npm	`n8n`	all versions	2.25.7`npm install n8n@2.25.7`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for n8n, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update n8n to 2.26.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54309 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-54309 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-54309. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Impact 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 in

O3 Security · Impact-Aware SCA

Is CVE-2026-54309 in your dependencies?

O3 Security finds CVE-2026-54309 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works

CVE-2026-54309 — n8n

EPSS Exploitation Probability

Real-World Exposure

Description

Impact

Patches

Workarounds

Affected Packages

Detection & mitigation playbook

Detect

Fix

Workarounds

How O3 protects you

Frequently Asked Questions

Is CVE-2026-54309 in your dependencies?