# Knock Knock plugin IP Whitelist bypass via an X-Forwarded-For HTTP header

Advisory record · `GHSA-wxvr-qqm7-6h65`

- **Identifiers:** `GHSA-wxvr-qqm7-6h65` · `CVE-2020-13485` · `PKSA-m63z-24sm-jgzh`
- **State:** Confirmed
- **Severity:** CVSS 9.1 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-697](https://cwe.mitre.org/data/definitions/697.html)
- **Tags:** [CWE-697](https://agentprime.io/advisories/tag/cwe-697.md)
- **Published:** 24 May 2022
- **Updated:** 24 Apr 2024
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 24 May 2022, 17:18 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.1: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `verbb/knock-knock` (Packagist): affected `<1.2.8`; fixed in `1.2.8`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The Knock Knock plugin for Craft CMS, versions before 1.2.8, can be bypassed through the IP whitelist by sending a crafted X-Forwarded-For HTTP header. An attacker with network access to the site can use this to get past the IP restriction. The source gives few details beyond this. Upgrade the verbb/knock-knock package to version 1.2.8 or later.

Written 4 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 9.1 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.014, the 71st percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:30 UTC: First seen by agentprime
- 31 Oct 2026, 14:30 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-wxvr-qqm7-6h65)

## Sources

- [GitHub Advisory Database: GHSA-wxvr-qqm7-6h65](https://github.com/advisories/GHSA-wxvr-qqm7-6h65)
- [OSV: GHSA-wxvr-qqm7-6h65](https://osv.dev/vulnerability/GHSA-wxvr-qqm7-6h65)
- <https://nvd.nist.gov/vuln/detail/CVE-2020-13485>
- <https://github.com/verbb/knock-knock>
- <https://github.com/verbb/knock-knock/blob/craft-3/CHANGELOG.md>
- <https://limpidsecurity.pl/security-advisories/1/knock-knock-plugin-for-craft-cms>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-wxvr-qqm7-6h65>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-wxvr-qqm7-6h65/>. Everything for agents: <https://agentprime.io/llms.txt>.