CVE-2021-47870Public exploitNetwork attack vector

Stored XSS via hex-escaped sender name

Published Jan 21, 2026 · Updated Jan 21, 2026

Stored XSS in the SMTP Contact plugin for GetSimple CMS 1.1.2 allows remote authenticated users to execute script in an administrator's browser. The settings handler stores the m_smtp_c_sender_name value after htmlspecialchars(), but JavaScript hex escapes survive filtering and decode into markup when rendered. A low-privileged authenticated user must save the crafted setting, and script execution requires an administrator to load the affected interface; the script can act with that session.

CVSS severity4.8
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in the SMTP Contact plugin for GetSimple CMS 1.1.2 allows remote authenticated users to execute script in an administrator's browser. The settings handler stores the m_smtp_c_sender_name value after htmlspecialchars(), but JavaScript hex escapes survive filtering and decode into markup when rendered. A low-privileged authenticated user must save the crafted setting, and script execution requires an administrator to load the affected interface; the script can act with that session.

The record

CVE
CVE-2021-47870
Published
Jan 21, 2026
Updated
Jan 21, 2026
Vendor
GetSimple CMS
Product
My SMTP Contact Plugin
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GetSimple CMS · My SMTP Contact Pluginversion=1.1.2

Published CVSS scores

4.8VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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