XSS in Get-Simple Getsimplecms
CVE-2021-47870
GetSimple CMS My SMTP Contact Plugin 1.1.2 suffers from a Stored Cross-Site Scripting (XSS) vulnerability. The plugin attempts to sanitize user input using htmlspecialchars(), but this can be bypassed by passing dangerous characters as escaped hex bytes. This allows attackers to inject arbitrary client-side code that executes in the administrator's browser when visiting a malicious page.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (18.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000
Affected products
- Get-Simple Getsimplecms — versions 1.1.2
- Getsimple Cms My Smtp Contact Plugin — versions 1.1.2
Weakness classification (CWE)
References
- github.com/boku7/gsSMTP-Csrf2Xss2RCE/ (Exploit, technical-description, Third Party Advisory, exploit)
- get-simple.info (Product, product)
- github.com/GetSimpleCMS/GetSimpleCMS (Product, product)
- www.exploit-db.com/exploits/49798 (Exploit, VDB Entry, Third Party Advisory, exploit)
- www.vulncheck.com/advisories/getsimple-cms-my-smtp-contact-plugin-stored-xss (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2021-47870?
- CVE-2021-47870 is a medium-severity vulnerability in Get-Simple Getsimplecms, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-01-21.
- How severe is CVE-2021-47870?
- Medium severity. CVSS v3 base score is 5.4 out of 10.