CVE-2021-47733

MEDIUM 6.1

CMSimple 5.4 Cross-Site Scripting via HTML Unicode Encoding

CVSS Score

6.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-79
Vendor	cmsimple
Product	cmsimple
Published	Dec 23, 2025
Last Updated	Apr 7, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Affected Versions

Cmsimple / CMSimple

<=5.4

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

heinjame