What’s Vulnerable › Vulnerabilities

CVE-2021-47870: GetSimple CMS My SMTP Contact Plugin 1.1.2 - Stored XSS

• Severity: medium (CVSS 5.4 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: 2026-01-21 · updated 2026-06-17
• Weakness: CWE-79

Description

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.

Affected products

• GetSimpleCMS: 1.1.2

References

• http://get-simple.info
• https://github.com/GetSimpleCMS/GetSimpleCMS
• https://github.com/boku7/gsSMTP-Csrf2Xss2RCE/
• https://www.exploit-db.com/exploits/49798
• https://www.vulncheck.com/advisories/getsimple-cms-my-smtp-contact-plugin-stored-xss

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