CVE-2021-36851Network attack vector

Editor-level XSS via unsanitized color parameters

Published Apr 4, 2022 · Updated Apr 28, 2026

Cross-site scripting in Web-Settler Testimonial Slider 3.5.8.3 and earlier allows remote authenticated users to execute script via color parameters. The plugin fails to neutralize input supplied through mpsp_posts_bg_color, mpsp_posts_description_color, and mpsp_slide_nav_button_color before placing it in a generated page; public records do not identify the responsible function or output context. An Editor or higher WordPress role is required, and a viewer must load affected output for injected script to run in that viewer's browser.

CVSS severity5.4
Medium
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Web-Settler Testimonial Slider 3.5.8.3 and earlier allows remote authenticated users to execute script via color parameters. The plugin fails to neutralize input supplied through mpsp_posts_bg_color, mpsp_posts_description_color, and mpsp_slide_nav_button_color before placing it in a generated page; public records do not identify the responsible function or output context. An Editor or higher WordPress role is required, and a viewer must load affected output for injected script to run in that viewer's browser.

The record

CVE
CVE-2021-36851
Published
Apr 4, 2022
Updated
Apr 28, 2026
Vendor
Web-Settler
Product
Testimonial Slider – Free Testimonials Slider Plugin
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 4, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 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=<= 3.5.8.3 <=3.5.8.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Web-Settler · Testimonial Slider – Free Testimonials Slider Pluginversion=<= 3.5.8.3 <=3.5.8.3

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
4.1PatchstackCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

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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