n8n before 2.28.0 Authentication Bypass via test-webhook
n8n before 2.28.0 (and before 2.27.4 on the 2.27.x branch) registers the DELETE /${restEndpoint}/test-webhook/:id endpoint before authentication middleware is applied, allowing any unauthenticated network caller who knows a workflow ID to cancel that workflow's active test webhook registration. The impact is limited to disrupting in-progress test sessions; production webhooks, persistent workflow state, and stored data are not affected.
- Published
- Jul 22, 2026
- Updated
- Jul 27, 2026
- EPSS
- 0.6% · 47th percentile
- CWE
- CWE-306
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
25
Monitor
Low priority for now.
- CVSS
- 25 / 40 · 6.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · VulnCheck
- 6.3
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| n8n | n8n | cpe:2.3:a:n8n:n8n |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- n8n n8n2.27.0 and later · before 2.27.4
Versions reported by the vendor
Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.
n8n-io n8n
- 2.28.0, 2.27.4not affected
- before 2.28.0affected · semver
- before 2.27.4affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| npm | n8n | before 2.27.4 | 2.27.4 |
Same product
n8n: all recordsOther highest-scoring records for the same primary product.
- CVE-2025-68613n8n Vulnerable to Remote Code Execution via Expression InjectionKEV95Now
- CVE-2026-21858n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling63This week
- 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 Node43Plan
- CVE-2026-0863Sandbox escape in n8n Python task runner allows for arbitrary code execution on the underlying host.42Plan
- CVE-2026-21877n8n is vulnerable to Remote Code Execution via Arbitrary File Write41Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| n8n-io n8n | 2.27.4 | Vendor (CNA) |
| n8n-io n8n | 2.28.0 | Vendor (CNA) |
| npm:n8n | 2.27.4 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
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.
No dated events beyond publication.
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 researchersFinders, 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-2026-5430929 days apartn8n: n8n MCP Browser HTTP Transport Exposes Unauthenticated Browser-Control Sessions35Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
- CVE-2026-655910 days apartn8n before 1.123.64 Sanitizer Bypass Remote Code Execution35Monitor
- CVE-2026-655980 days apartn8n before 1.123.64 Remote Code Execution via Git Clone35Monitor
- CVE-2026-655930 days apartn8n before 1.123.64, 2.29.8, and 2.30.1 SSRF via Dynamic Node Parameters25Monitor
- CVE-2026-655900 days apartn8n before 2.30.1 Shell Sandbox Bypass on Linux Windows22Monitor
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-26-0612 · Jul 23, 2026(n8n Güvenlik Zafiyeti)
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
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-306 · Missing Authentication for Critical FunctionCVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Root cause
A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”
The bug in code
The whole CWE-306 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
// Added for the support teamapp.post("/maintenance/reset", resetDevice);Fixed
if (config.maintenanceEnabled) { app.post( "/maintenance/reset", requireSession, requireRole("admin"), resetDevice );}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/n8n-io/n8n/security/advisories/GHSA-33q9-f52j-gc75
- www.vulncheck.com/advisories/n8n-before-authentication-bypass-via-test-webhook
Vendor advisories and official records. Exploit/PoC links are deliberately left out.