What’s Vulnerable › Vulnerabilities

CVE-2021-23838

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-01-15 · updated 2026-06-17
• Weakness: CWE-79

Description

An issue was discovered in flatCore before 2.0.0 build 139. A reflected XSS vulnerability was identified in the media_filter HTTP request body parameter for the acp interface. The affected parameter accepts malicious client-side script without proper input sanitization. For example, a malicious user can leverage this vulnerability to steal cookies from a victim user and perform a session-hijacking attack, which may then lead to unauthorized access to the site.

Affected products

• Flatcore: through 2.0.0

References

• http://packetstormsecurity.com/files/160936/flatCore-CMS-XSS-File-Disclosure-SQL-Injection.html
• https://github.com/flatCore/flatCore-CMS
• https://sec-consult.com/vulnerability-lab/
• http://packetstormsecurity.com/files/160936/flatCore-CMS-XSS-File-Disclosure-SQL-Injection.html
• https://github.com/flatCore/flatCore-CMS
• https://sec-consult.com/vulnerability-lab/

Get alerted when CVE-2021-23838 or the next vulnerability affects your stack