Vulnerability · Published Feb 25, 2026 · Assigned by GitHub_M
CVE-2026-27493n8n has Unauthenticated Expression Evaluation via Form Node
Critical 9.5
In plain English
A critical-severity code injection in n8n from n8n-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.4% (higher than 72% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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. Even when the preconditions are met, the expression injection alone is limited to data accessible within the n8n expression context. Escalation to remote code execution requires chaining with a separate sandbox escape vulnerability. The issue has been fixed in n8n versions 2.10.1, 2.9.3, and 1.123.22. Users should upgrade to one of these versions or later to remediate the vulnerability. If upgrading is not immediately possible, administrators should consider the following temporary mitigations. Review usage of form nodes manually for above mentioned preconditions, disable the Form node by adding `n8n-nodes-base.form` to the `NODES_EXCLUDE` environment variable, and/or disable the Form Trigger node by adding `n8n-nodes-base.formTrigger` to the `NODES_EXCLUDE` environment variable. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | n8n | 1.123.22 | GHSA-75g8-rv7v-32f7 |
| npm | n8n | 2.9.3 | GHSA-75g8-rv7v-32f7 |
| npm | n8n | 2.10.1 | GHSA-75g8-rv7v-32f7 |
Affected products (as reported)
Weakness: CWE-94, CWE-95 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
References
- https://github.com/n8n-io/n8n/security/advisories/GHSA-75g8-rv7v-32f7 x_refsource_CONFIRM
- https://github.com/n8n-io/n8n/issues/19 x_refsource_MISC
- https://github.com/n8n-io/n8n/commit/562d867483e871b0f1e31776252e23bd721df75b x_refsource_MISC
- https://github.com/n8n-io/n8n/releases/tag/n8n@1.123.22 x_refsource_MISC
- https://github.com/n8n-io/n8n/releases/tag/n8n@2.10.1 x_refsource_MISC
- https://github.com/n8n-io/n8n/releases/tag/n8n@2.9.3 x_refsource_MISC