CVE-2020-13485Public exploitNetwork attack vector

Unauthenticated whitelist bypass via spoofed forwarding header

Published May 25, 2020 · Updated Aug 4, 2024

Authentication bypass in the Knock Knock plugin for Craft CMS before 1.2.8 allows remote attackers to access IP-whitelisted content. The IP whitelist trusts the attacker-controlled X-Forwarded-For header as the visitor address and compares it directly with allowed IPs. A request bearing an allowed address therefore passes the whitelist without the source host owning that address, exposing only content protected by this IP gate.

CVSS severity9.1
Critical
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in the Knock Knock plugin for Craft CMS before 1.2.8 allows remote attackers to access IP-whitelisted content. The IP whitelist trusts the attacker-controlled X-Forwarded-For header as the visitor address and compares it directly with allowed IPs. A request bearing an allowed address therefore passes the whitelist without the source host owning that address, exposing only content protected by this IP gate.

The record

CVE
CVE-2020-13485
Published
May 25, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-697, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.4NVDAV:N/AC:L/Au:N/C:P/I:P/A:N
9.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-697Incorrect Comparison
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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