VulnerabilityPublished 8 May 2026Updated 12 May 2026

CVE-2026-42282: czlonkowski n8n-mcp · Sensitive Data in Logs

Affects czlonkowski n8n-mcpSource CVE Database V5

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Not known to be exploited · CVSS 4.3 Medium : upgrade to 2.47.13 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

4.3Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.47.13

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: Low
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
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 8 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 2.47.13.

Affected software

Product	Affected	Fixed in
czlonkowskin8n-mcp	Affected <2.47.13	Fixed in 2.47.13
GitHubczlonkowski/n8n-mcp`pkg:github/czlonkowski/n8n-mcp`Other threats	Affected <2.47.13	Fixed in 2.47.13

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AI-suggested

Upgrade n8n-mcp to version 2.47.13 or later, where this logging issue has been patched. Until the upgrade, restrict access to server logs to trusted personnel only and avoid running n8n-mcp in HTTP transport mode if possible. Since the vulnerability requires authentication, ensure strong authentication controls are in place. Patch status is not explicitly stated in vendor advisory fields, but the description confirms the issue is fixed in version 2.47.13.

Description

### Impact When `n8n-mcp` runs in HTTP transport mode, authenticated MCP `tools/call` requests had their full arguments and JSON-RPC params written to server logs by the request dispatcher and several sibling code paths before any redaction. When a tool call carries credential material — most notably `n8n_manage_credentials.data` — the raw values can be persisted in logs. In deployments where logs are collected, forwarded to external systems, or viewable outside the request trust boundary (shared log storage, SIEM pipelines, support/ops access), this can result in disclosure of: - bearer tokens and OAuth credentials sent through `n8n_manage_credentials` - per-tenant API keys and webhook auth headers embedded in tool arguments - arbitrary secret-bearing payloads passed to any MCP tool The issue requires authentication (`AUTH_TOKEN` accepted by the server), so unauthenticated callers cannot trigger it; the runtime exposure is also reduced by an existing console-silencing layer in HTTP mode, but that layer is fragile and the values are still constructed and passed into the logger. The fix removes the leak at the source. Impact category: **CWE-532** (Insertion of Sensitive Information into Log File). CVSS 3.1 score: **4.3 Medium** (`AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`). ### Affected Deployments running n8n-mcp **v2.47.12 or earlier** in HTTP transport mode (`MCP_MODE=http`). The stdio transport short-circuits the relevant log calls and is not affected in practice. ### Patched **v2.47.13** and later. - npm: `npx n8n-mcp@latest` (or pin to `>= 2.47.13`) - Docker: `docker pull ghcr.io/czlonkowski/n8n-mcp:latest` The patch routes tool-call arguments through a metadata-only summarizer (`summarizeToolCallArgs`) that records type, top-level key names, and approximate size — never values. The same pattern was adopted earlier for HTTP request bodies in GHSA-pfm2-2mhg-8wpx. ### Workarounds If developers cannot upgrade immediately: - Restrict access to the HTTP port (firewall, reverse proxy, or VPN) so only trusted clients can authenticate. - Restrict access to server logs (no shared SIEM ingestion, no support read-only access) until the upgrade lands. - Switch to stdio transport (`MCP_MODE=stdio`, the default for CLI invocation), which has no HTTP surface and short-circuits the affected log calls. ### Credit n8n-MCP thanks [@Mirr2](https://github.com/Mirr2) (Organization / Jormungandr) for reporting this issue.

Impact

Sensitive credential material such as bearer tokens, OAuth credentials, API keys, and other secrets can be exposed in server logs if the vulnerable version of n8n-mcp is used in HTTP transport mode. This exposure can lead to unauthorized access if logs are collected, forwarded externally, or accessible beyond the trusted request boundary. However, exploitation requires authentication, which limits the attack surface. There is no indication of impact to integrity or availability. No known exploits in the wild have been reported.

Summary

The n8n-mcp server, used to provide AI assistants access to n8n node documentation and operations, had a vulnerability (CWE-532) where sensitive credential data passed in authenticated MCP tool calls were logged in plaintext in server logs when operating in HTTP transport mode. This included bearer tokens, OAuth credentials, API keys, webhook authentication headers, and arbitrary secret payloads. The logging occurred before any redaction and despite a console-silencing layer, the sensitive data was constructed and passed to the logger. The vulnerability requires an authenticated request (valid AUTH_TOKEN) and affects versions prior to 2.47.13. The issue was patched in version 2.47.13 to prevent sensitive information leakage via logs.

CWE-532Insertion of Sensitive Information into Log File (opens in a new tab)
Base weaknessLikelihood of exploit: MediumOWASP Top 10 A09:2025: Security Logging & Alerting Failures (opens in a new tab)
The product writes sensitive information to a log file.
Architecture and Design · Implementation
Consider seriously the sensitivity of the information written into log files. Do not write secrets into the log files.
Distribution
Remove debug log files before deploying the application into production.
Operation
Protect log files against unauthorized read/write.
OWASP Cheat Sheets
Application Logging Vocabulary (opens in a new tab)
Logging (opens in a new tab)
OWASP ASVS 4.0.3
V7.1.1 (opens in a new tab)
V7.1.2 (opens in a new tab)
V8.3.5 (opens in a new tab)
Attack patterns
Fuzzing for application mapping (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 16 May 2026, 10:02 UTC

WeaknessesCWE-532

Technical details

References

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