PT-2026-36905 · N8N · N8N

Oscarbataille · Published 2026-04-22 · Updated 2026-05-13 · CVE-2026-42235

Positive Technologies (AI Summary)

CVSS v3.1

10

Critical

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions n8n versions prior to 1.123.32 n8n versions prior to 2.17.4 n8n versions prior to 2.18.1

Description An unauthenticated attacker can register a malicious MCP OAuth client using a crafted client name. If a victim user authorizes the OAuth consent dialog and a second user later revokes that access, a toast notification renders the injected script. Clicking the link executes arbitrary JavaScript within the victim's authenticated browser session, which can lead to the theft of credentials and session tokens, manipulation of workflows, or privilege escalation.

Recommendations Update to version 1.123.32. Update to version 2.17.4. Update to version 2.18.1.

Fix

LPE

XSS

Weakness Enumeration

CWE-79

CWE-87

Related Identifiers

BDU:2026-06872

CVE-2026-42235

GHSA-537J-GQPC-P7FQ

Affected Products

N8N

References · 12

• https://github.com/n8n-io/n8n/security/advisories/GHSA-537j-gqpc-p7fq · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-537j-gqpc-p7fq · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-42235 · Security Note
• https://bdu.fstec.ru/vul/2026-06872 · Security Note
• https://github.com/n8n-io/n8n · Note
• https://t.me/CVEtracker/52662 · Telegram Post
• https://twitter.com/lyrie_ai/status/2054408683602251878 · Twitter Post
• https://twitter.com/lyrie_ai/status/2054408682658505094 · Twitter Post
• https://twitter.com/lyrie_ai/status/2054408684613124319 · Twitter Post
• https://twitter.com/CVEnew/status/2051383967446712691 · Twitter Post
• https://twitter.com/lyrie_ai/status/2054408681765097929 · Twitter Post
• https://twitter.com/VulmonFeeds/status/2051521407570375074 · Twitter Post