CVE-2021-48016: DedeCMS 5.8.1-beta Unauthenticated RCE via plus/flink.php

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-22 · updated 2026-10-29
Weakness: CWE-94

Description

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.

Affected products

DedeCMS: through 5.8.1-beta

References

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

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