CyberSecBulletin
CVE-2026-59206NVD status: Analyzed

n8n: Improperly Controlled Modification of Object Prototype Attributes

Published Updated By the CyberSecBulletin desk

CVE-2026-59206 is a high-severity improperly controlled modification of object prototype attributes vulnerability in n8n, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected n8n versions: >= 2.28.0, < 2.28.1; >= 2.0.0-rc.0, < 2.27.4; < 1.123.61. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of n8n you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
n8nn8n>= 2.28.0, < 2.28.1; >= 2.0.0-rc.0, < 2.27.4; < 1.123.61Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
LowPerformance or availability is reduced.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.07.1HighCNA (github.com)
CVSS 3.17.1HighNVD

Official description

n8n is an open source workflow automation platform. Prior to 1.123.61, 2.27.4, and, 2.28.1, an authenticated user with the default workflow:create permission could pollute Object.prototype through a crafted workflow saved, updated, or imported via the workflow API, allowing unauthenticated requests to be treated as a privileged user and exposing user and project listing endpoints. This issue is fixed in versions 1.123.61, 2.27.4, and 2.28.1.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improperly Controlled Modification of Object Prototype Attributes

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

How developers prevent this class of flaw

  • By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
  • By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
  • When handling untrusted objects, validating using a schema can be used.

More Improperly Controlled Modification of Object Prototype Attributes vulnerabilities (CWE-1321)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in n8n

All n8n vulnerabilities

Recent Improperly Controlled Modification of Object Prototype Attributes vulnerabilities

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