CVE-2021-48016

DedeCMS through 5.8.1-beta contains a PHP code injection vulnerability in ShowMsg() where the HTTP Referer header is written into a DedeTemplate string and included. Unauthenticated attackers can send a crafted Referer to /plus/flink.php?dopost=save with an empty validate code to execute arbitrary PHP and system commands. Exploitation evidence was first observed by the Shadowserver Foundation on 2023-10-14.

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

• https://github.com/dedecms/DedeCMS/blob/v5.8.1/include/common.func.php
• https://github.com/projectdiscovery/nuclei-templates/blob/main/http/vulnerabilities/dedecms/dedecms-rce.yaml
• https://srcincite.io/blog/2021/09/30/chasing-a-dream-pwning-the-biggest-cms-in-china.html
• https://www.vulncheck.com/advisories/dedecms-5.8.1-beta-unauthenticated-rce-via-plus-flink-php