CVE-2021-47870

Name: CVE-2021-47870
Creator: NVD / NIST
Published: 2026-01-21T18:16:19.423+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.8/10EPSS 0.23%

Last modified Jun 17, 2026

CVE-2021-47870 is a medium-severity vulnerability rated 4.8/10 on the CVSS scale. 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. EPSS estimates a 0.23% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

5.4/10

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

CVSS 4.0

4.8/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.23%

13.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Get-Simple	Getsimplecms	1.1.2

References

http://get-simple.infoProduct
https://github.com/GetSimpleCMS/GetSimpleCMSProduct
https://github.com/boku7/gsSMTP-Csrf2Xss2RCE/Exploit, Third Party Advisory
https://www.exploit-db.com/exploits/49798Exploit, Third Party Advisory, VDB Entry
https://www.vulncheck.com/advisories/getsimple-cms-my-smtp-contact-plugin-stored-xssThird Party Advisory

Timeline

Published: Jan 21, 2026
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-47870?

How severe is CVE-2021-47870?

CVE-2021-47870 has a CVSS score of 4.8/10 (MEDIUM severity). The EPSS model estimates a 0.23% probability of exploitation in the next 30 days.

How do I fix CVE-2021-47870?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-47870?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST