n8n: Webhook Node IP Whitelist Bypass via Partial String Matching

Description

Impact

The Webhook node’s IP whitelist validation performed partial string matching instead of exact IP comparison. As a result, an incoming request could be accepted if the source IP address merely contained the configured whitelist entry as a substring.

This issue affected instances where workflow editors relied on IP-based access controls to restrict webhook access. Both IPv4 and IPv6 addresses were impacted. An attacker with a non-whitelisted IP could bypass restrictions if their IP shared a partial prefix with a trusted address, undermining the intended security boundary.

Patches

This issue has been patched in version 2.2.0.

Users are advised to upgrade to v2.2.0 or later, where IP whitelist validation uses strict IP comparison logic rather than partial string matching.

Workarounds

Users unable to upgrade immediately should avoid relying solely on IP whitelisting for webhook security. Recommended mitigations include:
- Adding authentication mechanisms such as shared secrets, HMAC signatures, or API keys.
- Avoiding short or prefix-based whitelist entries.
- Enforcing IP filtering at the network layer (for example, via reverse proxies or firewalls).

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-01-13 14:57:12 UTC
Updated
2026-01-13 21:40:43 UTC
GitHub reviewed
2026-01-13 14:57:12 UTC
NVD published
2026-01-13

EPSS Score

Score Percentile
0.04% 11.67%

CVSS Scores

Base score Version Severity Vector
5.3 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

CWEs

CWE id Name
CWE-134 Use of Externally-Controlled Format String
CWE-183 Permissive List of Allowed Inputs
CWE-284 Improper Access Control

Credits

  • berkdedekarginoglu (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
npm n8n >= 1.36.0, < 2.2.0 2.2.0

References

cvelogic Threat Intelligence