CVE intelligence and bounded remediation

CVE-2026-27493 — n8n is an open source workflow automation platform

Critical CVSS 9.5

n8n is an open source workflow automation platform. Prior to versions 2.10.1, 2.9.3, and 1.123.22, a second-order expression injection vulnerability existed in n8n's Form nodes that could allow an unauthenticated attacker to inject and evaluate arbitrary n8n expressions by submitting crafted form data. When chained with an expression sandbox escape, this could escalate to remote code execution on the n8n host. The vulnerability requires a specific workflow configuration to be exploitable. First, a form node with a field interpolating a value provided by an unauthenticated user, e.g. a form submitted value. Second, the field value must begin with an `=` character, which caused n8n to treat it as an expression and triggered a double-evaluation of the field content. There is no practical reason for a workflow designer to prefix a field with `=` intentionally — the character is not rendered in the output, so the result would not match the designer's expectations. If added accidentally, it would be noticeable and very unlikely to persist. An unauthenticated attacker would need to either know about this specific circumstance on a target instance or discover a matching form by chance. Ev…

Severity
Critical
CVSS
9.5 (4.0)
Published
2026-02-25
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-94, CWE-95

Affected products

  • n8n / n8n

Showing 1 representative product identities from 3 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Command, code, expression, and template injection

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Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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