Information -------------------- Advisory by Netsparker Name: XSS Vulnerability in MailPoet Newsletters Affected Software : MailPoet Newsletters Affected Versions: v2.6.19 and possibly below Vendor Homepage : http://www.mailpoet.com/ Vulnerability Type : Cross-site Scripting Severity : Important CVE-ID : TBA Status : Fixed Netsparker Advisory Reference : NS-16-002 Description -------------------- By exploiting a Cross-site scripting vulnerability the attacker can hijack a logged in user?s session. This means that the malicious hacker can change the logged in user?s password and invalidate the session of the victim while the hacker maintains access. As seen from the XSS example in this article, if a web application is vulnerable to cross-site scripting and the administrator?s session is hijacked, the malicious hacker exploiting the vulnerability will have full admin privileges on that web application. Technical Details -------------------- Proof of Concept URL for XSS in MailPoet Newsletters v2.6.19: wordpress-4.4.1/?wysija-page=1&controller=confirm&wysija-key='"--></style></scRipt><scRipt>alert(0x0034B4)</scRipt>&action=unsubscribe&demo=1&wysijap=subscriptions For more information on cross-site scripting vulnerabilities read the following article: https://www.netsparker.com/web-vulnerability-scanner/vulnerability-security-checks-index/cross-site-scripting-xss/ Advisory Timeline -------------------- 18 Jan 2016 - First Contact 29 Jan 2016 - Vendor Fixed 02 Feb 2016 - Advisory Released Solution -------------------- Patch released by MailPoet and annocunced here: https://wordpress.org/plugins/wysija-newsletters/changelog/. Download the latest version. Credits & Authors -------------------- These issues have been discovered by Omar Kurt while testing Netsparker Web Application Security Scanner - https://www.netsparker.com/web-vulnerability-scanner/. About Netsparker -------------------- 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 engine?s 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. Onur Y?lmaz - National General Manager Netsparker Web Application Security Scanner T: +90 (0)554 873 0482