VulnerabilityPublished 29 May 2026

CVE-2026-45582: czlonkowski n8n-mcp · Insertion of Sensitive Information Into Sent Data

Affects czlonkowski n8n-mcpSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium : upgrade to 2.51.3 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.51.3

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade n8n-mcp and czlonkowski/n8n-mcp to 2.51.3.

Affected software

Product	Affected	Fixed in
czlonkowskin8n-mcp	Affected <2.51.3	Fixed in 2.51.3
GitHubczlonkowski/n8n-mcp`pkg:github/czlonkowski/n8n-mcp`Other threats	Affected <2.51.3	Fixed in 2.51.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade n8n-mcp to version 2.51.3 or later, where the telemetry sanitizer properly removes sensitive URL parameter fragments before sending telemetry data. Patch status is confirmed by the vendor advisory stating the issue is fixed in 2.51.3. No additional mitigation steps are indicated.

Description

## Summary In affected versions of n8n-mcp, the workflow telemetry sanitizer could retain partial fragments of URL-shaped node parameters before sending workflow data to the project's anonymous telemetry backend. Values placed in HTTP-Request-style node parameters — such as customer or tenant identifiers, short secrets embedded in query strings, and signed request parameters — could therefore appear in stored telemetry, contrary to the collection boundary documented in `PRIVACY.md`. ## Impact Operators with access to the project's telemetry backend could read partial fragments of workflow URL parameters that should not have been collected. The bug was scoped to URL-shaped fields in workflow *definitions*; credentials, OAuth tokens, and workflow *execution* data are not affected — credentials are removed by a separate code path, and long secrets and known-provider tokens are matched by dedicated patterns. ## Patches Fixed in **n8n-mcp `2.51.3`**. Upgrading is the recommended remediation. ## Workarounds For users who cannot upgrade immediately, disable anonymous telemetry by setting any of these environment variables to `true`: - `N8N_MCP_TELEMETRY_DISABLED` - `TELEMETRY_DISABLED` - `DISABLE_TELEMETRY` ## Credit Reported by @u-ktdi.

Impact

Sensitive information such as customer or tenant identifiers and short secrets embedded in URL parameters could be inadvertently included in telemetry data sent to the anonymous backend. This could lead to unintended exposure of sensitive data outside the intended collection boundary. There is no indication of impact on data integrity or availability, and no known exploits in the wild have been reported.

Summary

The n8n-mcp server prior to version 2.51.3 contained a vulnerability (CWE-201) where the workflow telemetry sanitizer failed to fully remove sensitive information embedded in HTTP-Request-style node parameters before sending telemetry data. This caused partial fragments of sensitive URL parameters, including customer or tenant identifiers and short secrets in query strings, to be included in telemetry sent to the anonymous backend. This behavior violates the privacy boundary defined in the project's PRIVACY.md documentation. The vulnerability is addressed by updating to version 2.51.3, which corrects the telemetry sanitizer to prevent sensitive data leakage.

CWE-201Insertion of Sensitive Information Into Sent Data (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.
Requirements
Specify which data in the software should be regarded as sensitive. Consider which types of users should have access to which types of data.
Implementation
Ensure that any possibly sensitive data specified in the requirements is verified with designers to ensure that it is either a calculated risk or mitigated elsewhere.
System Configuration
Setup default error messages so that unexpected errors do not disclose sensitive information.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Choosing Message Identifier (opens in a new tab)
Exploiting Incorrectly Configured SSL/TLS (opens in a new tab)
WiFi MAC Address Tracking (opens in a new tab)
WiFi SSID Tracking (opens in a new tab)
Cellular Broadcast Message Request (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 May 2026, 14:05 UTC

WeaknessesCWE-201

Technical details

References

Community reviews

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