XSS in Cmsimple
CVE-2021-47733
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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (16.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Cmsimple — versions <=5.4, 5.4
Weakness classification (CWE)
References
- www.exploit-db.com/exploits/50612 (Exploit, exploit)
- www.cmsimple.org/en/ (Product, product)
- www.vulncheck.com/advisories/cmsimple-cross-site-scripting-via-html-unicode-enc… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2021-47733?
- CVE-2021-47733 is a medium-severity vulnerability in Cmsimple, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2025-12-23.
- How severe is CVE-2021-47733?
- Medium severity. CVSS v3 base score is 6.1 out of 10.