CVE-2026-21858
n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling
Description
n8n is an open source workflow automation platform. Versions starting with 1.65.0 and below 1.121.0 enable an attacker to access files on the underlying server through execution of certain form-based workflows. A vulnerable workflow could grant access to an unauthenticated remote attacker, resulting in exposure of sensitive information stored on the system and may enable further compromise depending on deployment configuration and workflow usage. This issue is fixed in version 1.121.0.
INFO
Published Date :
Jan. 8, 2026, 12:15 a.m.
Last Modified :
Jan. 8, 2026, 8:15 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | [email protected] |
Solution
- Update n8n to version 1.121.0.
- Apply security patches for affected versions.
- Review and secure workflow configurations.
Public PoC/Exploit Available at Github
CVE-2026-21858 has a 4 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-21858.
| URL | Resource |
|---|---|
| https://github.com/n8n-io/n8n/security/advisories/GHSA-v4pr-fm98-w9pg |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-21858 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-21858
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
CVE-2026-21858
n8n Ni8mare - Unauthenticated Arbitrary File Read to RCE Chain (CVSS 10.0)
exploit n8n poc rce security vulnerability cve-2026-21858 ni8mare
Dockerfile Python Shell
A maximum severity vulnerability dubbed "Ni8mare" allows remote, unauthenticated attackers to take control over locally deployed instances of the N8N workflow automation platform.
SecDB - Security Feeds
cve security-feeds vulnerability
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-21858 vulnerability anywhere in the article.
-
security.nl
NCSC verwacht misbruik van kritieke Ni8mare-kwetsbaarheid in n8n
Het Nationaal Cyber Security Centrum (NCSC) verwacht dat aanvallers misbruik zullen gaan maken van een kritieke kwetsbaarheid in n8n, aangeduid als Ni8mare en CVE-2026-21858, waardoor ongeauthenticeer ... Read more
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The Register
Maximum-severity n8n flaw lets randos run your automation server
A maximum-severity bug in the popular automation platform n8n has left an estimated 100,000 servers wide open to complete takeover, courtesy of a flaw so bad it doesn't even require logging in. The vu ... Read more
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Daily CyberSecurity
CISA KEV Alert: HPE’s Maximum CVSS Score Flaw and a Zombie PowerPoint Bug
The Cybersecurity and Infrastructure Security Agency (CISA) has updated its Known Exploited Vulnerabilities (KEV) Catalog with two new entries that span nearly two decades of computing history. The la ... Read more
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Daily CyberSecurity
Public Exploit Released: Critical n8n Flaw CVE-2026-21858 Exposes 100k Servers
The “central nervous system” of automation for thousands of companies has a critical weakness. A new report from Cyera reveals a devastating vulnerability in n8n, the popular workflow automation platf ... Read more
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Daily CyberSecurity
“VM Isolation is Not Absolute”: Researchers Unmask Sophisticated ESXi “Maestro” Exploit
In a new report, the Huntress Tactical Response Team details a sophisticated intrusion discovered in December 2025 where threat actors successfully executed a “VM escape”—breaking out of a guest virtu ... Read more
The following table lists the changes that have been made to the
CVE-2026-21858 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
Jan. 08, 2026
Action Type Old Value New Value Changed Description n8n is an open source workflow automation platform. Versions below 1.121.0 enable an attacker to access files on the underlying server through execution of certain form-based workflows. A vulnerable workflow could grant access to an unauthenticated remote attacker, resulting in exposure of sensitive information stored on the system and may enable further compromise depending on deployment configuration and workflow usage. This issue is fixed in version 1.121.0. n8n is an open source workflow automation platform. Versions starting with 1.65.0 and below 1.121.0 enable an attacker to access files on the underlying server through execution of certain form-based workflows. A vulnerable workflow could grant access to an unauthenticated remote attacker, resulting in exposure of sensitive information stored on the system and may enable further compromise depending on deployment configuration and workflow usage. This issue is fixed in version 1.121.0. -
New CVE Received by [email protected]
Jan. 08, 2026
Action Type Old Value New Value Added Description n8n is an open source workflow automation platform. Versions below 1.121.0 enable an attacker to access files on the underlying server through execution of certain form-based workflows. A vulnerable workflow could grant access to an unauthenticated remote attacker, resulting in exposure of sensitive information stored on the system and may enable further compromise depending on deployment configuration and workflow usage. This issue is fixed in version 1.121.0. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N Added CWE CWE-20 Added Reference https://github.com/n8n-io/n8n/security/advisories/GHSA-v4pr-fm98-w9pg