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NVD / CVE Program· CNA GitHub_M

CVE-2026-21858: n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling

Noroxi assessment

Priority: This week (action score 63/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 78.1% (FIRST EPSS); higher than 99.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: n8n-io n8n 1.121.0.

Don’t wait for the next maintenance window. Upgrade to n8n-io n8n 1.121.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

CriticalCVSS 10.0 · v3.1—Proof of concept Fix available
Published
Jan 7, 2026
Updated
Jun 17, 2026
EPSS
78.1% · 99th percentile

Report tools

JSON

Action score

63

This week

Don’t wait for the next maintenance window.

CVSS
40 / 40 · 10.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
23 / 30 · 78.1%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
10.0
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-21858

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
n8nn8n

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • n8n n8n1.65.0 and later · before 1.121.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • n8n-io n8n

    • >= 1.65.0, < 1.121.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
npmn8nfrom 1.65.0 · before 1.121.01.121.0

Same product

n8n: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-68613n8n Vulnerable to Remote Code Execution via Expression InjectionKEV
    95Now
  • CVE-2026-1470Authenticated users can bypass the Expression sandbox mechanism to achieve full remote code execution on n8n’s main node.
    45Plan
  • CVE-2025-68668n8n Vulnerable to Arbitrary Command Execution in Pyodide based Python Code Node
    43Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-61914Dec 26, 2025 · n8n's Possible Stored XSS in "Respond to Webhook" Node May Execute Outside iframe Sandbox
    21Monitor
  • ← EarlierCVE-2025-68697Dec 26, 2025 · Self-hosted n8n has Legacy Code node that enables arbitrary file read/write
    21Monitor
  • Later →CVE-2026-21877Jan 7, 2026 · n8n is vulnerable to Remote Code Execution via Arbitrary File Write
    41Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
n8n-io n8n1.121.0 · descriptionVendor (CNA)
npm:n8n1.121.0Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×16

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2026-21858 —
Proof-of-concept repository on GitHubstars:3052026-01-07
Proof-of-concept repository on GitHubstars:22026-01-12
Proof-of-concept repository on GitHubstars:02026-01-17
Proof-of-concept repository on GitHubstars:12026-01-20
Proof-of-concept repository on GitHubstars:32026-01-20
Proof-of-concept repository on GitHubstars:02026-01-28
Proof-of-concept repository on GitHubstars:02026-01-30
Proof-of-concept repository on GitHubstars:12026-02-11
Proof-of-concept repository on GitHubstars:12026-02-23
Proof-of-concept repository on GitHubstars:02026-04-09
Proof-of-concept repository on GitHubstars:02026-04-16

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-1 d
  2. Published
  3. TodayNov 10, 2026+307 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-2189328 days apartn8n Vulnerable to Command Injection in Community Package Installation
    37Monitor
  • CVE-2026-49444167 days apartn8n: Python sandbox escape
    28Monitor
  • CVE-2026-85170239 days apartn8n before 1.123.73 Local File Read and SSRF via Gmail and Brevo nodes
    28Monitor
  • CVE-2026-56349189 days apartn8n - Guardrail Node Bypass via Crafted Input
    25Monitor
  • CVE-2026-2563130 days apartDomain allowlist bypass enables credential exfiltration
    21Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-20 · Improper Input Validation

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records