usd-2018-0028 | Icinga Web 2/2.6.1

Advisory ID: usd-2018-0028
CVE number: CVE-2018-18248
Affected Product: Icinga Web 2
Affected Version: 2.6.1
Vulnerability Type: Reflected XSS
Security Risk: medium
Vendor URL:
Vendor Status: Won’t fix


Reflected XSS attack (or non-persistent attack) occur when a malicious script is reflected off of a web application to the victim’s browser. The attack is typically delivered via email or a web site and activated through a link, which sends a request to a website with a vulnerability that enables execution of malicious scripts.

Proof of Concept

Icinga Web 2 does not properly validate and encode parameters received through HTTP GET requests. When the following URLs are requested by an authenticated user the HTTP response will contain malicious JavaScript:




The following URL requires the setup module to be enabled but does not require the victim to be authenticated:


Since the payloads is introduced through the URL, some modern browsers will encode the special characters (´'“ etc.) or detect the XSS attempt and block the request. This should mitigate the effects of this vulnerability in most real-world cases.


Make sure to validate the user supplied input and encode the output.


  • 2018-09-12 First contact request via
  • 2018-10-02 Vendor received advisories via
  • 2018-10-11 CVE-ID requested
  • 2018-10-12 received CVE ID and notified vendor about it
  • 2018-11-08 vendor states that they won’t fix the vulnerability as in their opinion it is already handled reasonable by browsers
  • 2018-11-09 extended public disclosure deadline to 2018-11-25
  • 2018-12-07 Security advisory released


These security vulnerabilities were found by Maximilian Boehner of usd AG.


In order to protect businesses against hackers and criminals, we always have to keep our skills and knowledge up to date. Thus, security research is just as important for our work as is building up a security community to promote the exchange of knowledge. After all, more security can only be achieved if many individuals take on the task.

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to usd AG

In accordance with usd AG’s Responsible Disclosure Policy, all vendors have been notified of the existence of these vulnerabilities.


The information provided in this security advisory is provided „as is“ and without warranty of any kind. Details of this security advisory may be updated in order to provide as accurate information as possible.