Open Redirection Vulnerability in GetSimpleCMS 3.3.13

Information
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Advisory by Netsparker
Name: Open Redirection Vulnerability in GetSimpleCMS
Affected Software: GetSimpleCMS
Affected Versions: 3.3.13
Homepage: http://get-simple.info/
Vulnerability: Open Redirection
Severity: Medium
Status: Not Fixed
CVSS Score (3.0): AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Netsparker Advisory Reference: NS-18-056

Technical Details
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URL  : http://GetSimpleCMS-3.3.13/admin/index.php?redirect=http://r87.com/?localhost/  Parameter Name : redirect
Parameter Type  : GET
Attack Pattern  : http://r87.com/?localhost/  
Github: https://github.com/GetSimpleCMS/GetSimpleCMS/issues/1300

For more information on Open Redirection vulnerabilities read the article Open Redirection.

Advisory Timeline
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12th November 2018 - First Contact
12th November 2018 - Disclosed Publicly at Request
14th Febuary 2019 - Advisory Released

Credits & Authors
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These issues have been discovered by Mithat GAPgebakan while testing Netsparker Web Application Security Scanner.

About Netsparker
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Netsparker web application security scanners find and report security flaws and vulnerabilities such as SQL Injection and Cross-site Scripting (XSS) in all websites and web applications, regardless of the platform and technology they are built on. Netsparker scanning engineas unique detection and exploitation techniques allow it to be dead accurate in reporting vulnerabilities. The Netsparker web application security scanner is available in two editions; Netsparker Desktop and Netsparker Cloud. Visit our website https://www.netsparker.com for more information.