What’s Vulnerable › Vulnerabilities

CVE-2021-47733: CMSimple 5.4 Cross-Site Scripting via HTML Unicode Encoding

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-12-23 · updated 2026-06-17
• Weakness: CWE-79

Description

CMSimple 5.4 contains a cross-site scripting vulnerability that allows attackers to bypass input filtering by using HTML to Unicode encoding. Attackers can inject malicious scripts by encoding payloads like ')-alert(1)// and execute arbitrary JavaScript when victims interact with delete buttons.

Affected products

• CMSimple: 5.4

References

• https://www.cmsimple.org/en/
• https://www.exploit-db.com/exploits/50612
• https://www.vulncheck.com/advisories/cmsimple-cross-site-scripting-via-html-unicode-encoding

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