Which versions of Getsimplecms are affected by CVE-2021-47870?

CVE-2021-47870 presents moderate security risk, a cross-site scripting vulnerability rated CVSS 5.4. Attackers could inject scripts to steal sessions or perform actions as authenticated users.

Is there a public PoC exploit available for CVE-2021-47870?

Yes, a public proof-of-concept exploit is available for CVE-2021-47870. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2021-47870?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Getsimplecms CVE-2021-47870

Q: What is the CVSS score of CVE-2021-47870?

CVE-2021-47870 has a CVSS 4.0 base score of 4.8 (Medium). CVSS vector: 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 exploitation probability: 0.1%.

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-01-21 disclosure@vulncheck.com

XSS Getsimplecms

4.8

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

4.8 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Scope

Lifecycle Timeline

CVSS changed

May 12, 2026 - 22:22 NVD

5.4 (MEDIUM) 4.8 (MEDIUM)

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

PoC Detected

Mar 06, 2026 - 20:10 vuln.today

Public exploit code

CVE Published

Jan 21, 2026 - 18:16 nvd

MEDIUM 5.4

DescriptionCVE.org

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.

AnalysisAI

Technical ContextAI

Classified as CWE-79 (Cross-site Scripting (XSS)). Affects Getsimplecms. 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.

RemediationAI

Monitor vendor advisories for a patch. Implement output encoding and Content Security Policy headers. Restrict network access to the affected service where possible.

CVE-2021-47870 vulnerability details – vuln.today

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