Summary
Workarounds
If upgrading is not immediately possible, administrators should consider the following temporary mitigations:
- Limit workflow creation and editing permissions to fully trusted users only.
- Never execute untrusted workflows.
- Review workflows that receive data from via webhooks, forms, or MCP servers to ensure they are communicating with trusted entities before executing them manually.
These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
n8n has adopted CVSS 4.0 as primary score for all security advisories. CVSS 3.1 vector strings are provided for backward compatibility.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Impact
A Cross-site Scripting (XSS) vulnerability has been identified in the handling of webhook responses and related HTTP endpoints. Under certain conditions, the Content Security Policy (CSP) sandbox protection intended to isolate HTML responses may not be applied correctly.
An authenticated user with permission to create or modify workflows could abuse this to execute malicious scripts with same-origin privileges when other users interact with the crafted workflow. This could lead to session hijacking and account takeover.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
The issue has been fixed in n8n versions 1.122.5 and 1.123.2. Users should upgrade to these versions or later to remediate the vulnerability.
Frequently Asked Questions
- What is CVE-2026-25051? CVE-2026-25051 is a high-severity cross-site scripting (XSS) vulnerability in n8n (npm), affecting versions >= 1.123.0, < 1.123.2. It is fixed in 1.123.2, 1.122.5. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- Which versions of n8n are affected by CVE-2026-25051? n8n (npm) versions >= 1.123.0, < 1.123.2 is affected.
- Is there a fix for CVE-2026-25051? Yes. CVE-2026-25051 is fixed in 1.123.2, 1.122.5. Upgrade to this version or later.
- Is CVE-2026-25051 exploitable, and should I be worried? Whether CVE-2026-25051 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-25051 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-25051?
- Upgrade
n8nto 1.123.2 or later - Upgrade
n8nto 1.122.5 or later
- Upgrade