Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-21858

n8n Vulnerable to Unauthenticated File Access

n8n-io / n8n · >= 1.65.0, < 1.121.0

Watch CVE-2026-21858 Browse KEV feed
Severity
CVSS 10.0 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
78.2%
First observed
29 Jul 2026
Last observed
14 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-21858 is an unauthenticated vulnerability affecting n8n-io n8n. 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...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence. Also confirmed by third-party sources.

Who is affected?

n8n-io / n8n >= 1.65.0, < 1.121.0.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

n8n is an open source workflow automation platform

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.

n8n-io Affected
n8n
>= 1.65.0, < 1.121.0
Published
07 Jan 2026
Exploitation Reported
07 Feb 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

The Shadowserver

Recorded 07 Feb 2026

A trusted third party reported exploitation.

Active exploitation observed

Previdian sensor

First observed 29 Jul 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
The Shadowserver First 2026-02-07 00:00 UTC
Previdian Sensors 2026-08-03 14:21 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

103

Attempts observed

5

Unique attacker IPs

2

Attacker countries

SE · UA

6

Sensors observed

CVE-2026-21858 exploitation attempts over the last 83 days

Daily events observed by Previdian sensors

Updated 18 Oct 2026

0
1
0
1
7
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
6
4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
20
0
20
0
0
0
0
0
0
0
20
0
20
0
0
0
0
28 Jul 14 Aug 31 Aug 17 Sep 18 Oct

First observed 29 Jul 2026 · Last observed 14 Oct 2026

Pro adds sensor region and window summaries. Enterprise adds raw IPs, paths, User-Agents, and payloads.

Start 14-day Pro trial

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
20
1
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-21858.yaml 01 Jun 2026

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

10.0 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

EPSS

78.2%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Input Validation CWE-20

Recent mention · RecordedFuture

August 2026 CVE Landscape

In August 2026, Insikt Group® identified 73 high-impact vulnerabilities that should be prioritized for remediation, 43 of which had a Very Critical Recorded Future Risk Score. This represents a 14% decrease from last month.

Read full advisory

All Mentions

Recent mention · RecordedFuture

August 2026 CVE Landscape

RecordedFuture · 08 Sep 2026

In August 2026, Insikt Group® identified 73 high-impact vulnerabilities that should be prioritized for remediation, 43 of which had a Very Critical Recorded Future Risk Score. This represents a 14% decrease from last month.

Recent mention · Tenable Blog

The Agentic AI threat cluster: Seven incidents, three actors, and what they mean for your exposure

Tenable Blog · 15 Aug 2026

Tenable’s Research Special Operations (RSO) team has been tracking a cluster of agentic AI threat activity since late July 2026. The Taiwan autonomous AI cyber attack confirmed what the cluster data already showed: near-autonomous offensive AI has crossed from theoretical risk to operational reality.Key TakeawaysTaiwan's Ministry of Digital Affairs confirmed a near-autonomous AI cyber attack in July 2026 in which autonomous agents mapped 21 connected government systems, compromised 85 accounts, and exfiltrated more than 2,564 personnel records in approximately four days.The Taiwan campaign...

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

ZeroDayEvil/CVE-2026-21858-n8n-FullChain

github · Created 2026-09-12 00:03:07 UTC · 0 stars · AI assessment 85%

🛡️ Official AI Security Tool module for CVE-2026-21858 + CVE-2025-68613 (n8n "Ni8mare" Unauthenticated Arbitrary File Read & Expression Injection RCE Full Chain).

n8n Webhooks - Remote Code Execution

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 03:10 UTC

    Indicators of compromise added (5)

    Indicators of compromise recorded

  2. 03:10 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  3. 14:21 UTC

    Public PoC available

    Public proof-of-concept code published

  4. 15:34 UTC

    Nuclei template available

    Scanner coverage available

  5. 00:00 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  6. 23:57 UTC

    CVE published

    Vulnerability disclosed publicly

  7. 16:44 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-21858

Sample API response 
{
  "cve_id": "CVE-2026-21858",
  "confidence": "Confirmed",
  "cvss_score": 10.0,
  "cvss_estimated": false,
  "epss_score": 0.78188,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 103, "sensors": 6 }
}