CVE-2021-38290Public exploitNetwork attack vector

Phishing link injection via untrusted Host header

Published Aug 9, 2021 · Updated Aug 4, 2024

Host header injection in FUEL CMS 1.5.0 and earlier allows remote attackers to generate links containing an attacker-controlled host. The fuel_constants.php base-path logic and Asset.php absolute-path builder concatenate the unvalidated HTTP Host header into generated URLs. Exploitation requires a crafted Host header to reach the application and a recipient to trust the resulting poisoned link, enabling phishing toward an attacker-selected host.

CVSS severity8.1
High
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Host header injection in FUEL CMS 1.5.0 and earlier allows remote attackers to generate links containing an attacker-controlled host. The fuel_constants.php base-path logic and Asset.php absolute-path builder concatenate the unvalidated HTTP Host header into generated URLs. Exploitation requires a crafted Host header to reach the application and a recipient to trust the resulting poisoned link, enabling phishing toward an attacker-selected host.

The record

CVE
CVE-2021-38290
Published
Aug 9, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-74, T1566
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 9, 2021CVE 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

8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1566Phishing

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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