Is CVE-2026-21858 actively exploited?

Yes. KEV Intelligence has observed exploitation attempts targeting this CVE. Confidence is confirmed.

What exploitation activity has KEV Intelligence observed?

KEV Intelligence sensors have observed 10 exploitation attempts, 2 unique attacker IPs, and 1 country targeting CVE-2026-21858. First observed Jul 29, 2026; last observed Aug 02, 2026.

Which versions are affected?

CVE-2026-21858 affects n8n-io n8n. Reported affected version: >= 1.65.0, < 1.121.0.

How should organizations remediate it?

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.

No. CVE-2026-21858 is not currently listed in CISA KEV.

Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-21858

Q: How should organizations remediate it?

Prioritize immediate patching and validate internet-facing exposure. Monitor for matching exploitation attempts in your environment.

Q: Is it in CISA KEV?

No. CVE-2026-21858 is not currently listed in CISA KEV.

n8n Vulnerable to Unauthenticated File Access

n8n-io / n8n · >= 1.65.0, < 1.121.0

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Severity: CVSS 10.0 · Critical
Confidence: Confirmed
Exploit status: Observed in sensors
EPSS: 72.5%
First observed: 29 Jul 2026
Last observed: 02 Aug 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. KEV Intelligence sensors observed exploitation attempts with confirmed confidence.

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.

Vendor Product Affected Status

n8n-io n8n >= 1.65.0, < 1.121.0 Affected

Published: 07 Jan 2026
Exploitation Reported: 07 Feb 2026
Attack vector: Remote
Complexity: Low
Privileges: None
User interaction: None

CVE References

CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-21858
https://github.com/n8n-io/n8n/security/advisories/GHSA-v4pr-fm98-w9pg github.com · CVE Record https://github.com/n8n-io/n8n/security/advisories/GHSA-v4pr-fm98-w9pg
https://www.cyera.com/research-labs/ni8mare-unauthenticated-remote-code-execution-in-n8n-cve-2026-21858 cyera.com · CVE Record https://www.cyera.com/research-labs/ni8mare-unauthenticated-remote-co...

Exploitation evidence

Why KEV Intelligence 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

Independent exploitation attestation added to the KEV Intelligence record.

Active exploitation observed

KEV Intelligence sensor

First observed 29 Jul 2026

First-party sensor telemetry confirms matching exploitation attempts.

Proof of concept available

GitHub

Recorded 07 Jan 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

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

Learn about Pro API access

Source	Added
The Shadowserver First	2026-02-07 00:00 UTC
KEV Intelligence	2026-08-03 14:21 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Aggregate observations show the scale, recency, and distribution of activity without overstating sparse data.

Attempts observed

Unique attacker IPs

Attacker countries

Sensors observed

Exploitation attempts over the last 23 days

Daily events observed by KEV Intelligence sensors

Updated 19 Aug 2026

28 Jul 2 Aug 7 Aug 12 Aug 19 Aug

First observed 29 Jul 2026 · Last observed 02 Aug 2026

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

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Detection

Operational artifacts and observed signals

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

Observed signals

Request targets: 4
User-Agents: 1

Raw values available in Pro and Enterprise.

Scanner coverage

Nuclei template detected 01 Jun 2026.

View Nuclei template

Virtual patch status

No KEV Intelligence 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

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

EPSS

72.5%

Weaknesses

Improper Input Validation CWE-20

Recent mention · Tenable Blog

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

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...

Read full advisory

Potential Proof of Concepts

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

n8n Webhooks - Remote Code Execution

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

29 Jul 2026
Observed by KEV Intelligence sensors

Evidence-backed exploitation signal
29 Jul 2026
Indicators of compromise added (2)

Indicators of compromise recorded
12 Jun 2026
Public PoC available

Public proof-of-concept code published
01 Jun 2026
Nuclei template available

Scanner coverage available
07 Feb 2026
Added to KEV Intelligence KEV Feed

High-confidence, third-party attested exploitation
07 Jan 2026
CVE published

Vulnerability disclosed publicly
05 Jan 2026
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.

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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

Free JSON includes basic KEV fields

{
  "cve_id": "CVE-2026-21858",
  "confidence": "Confirmed",
  "cvss_score": 10.0,
  "cvss_estimated": false,
  "epss_score": 0.72549,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 10, "sensors": 2 }
}

Early warning alerts

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