CVE-2021-36872Network attack vector

Authenticated stored XSS via unsanitized widget post type

Published Sep 23, 2021 · Updated Apr 28, 2026

Stored cross-site scripting in Hector Cabrera WP Popular Posts 5.3.3 and earlier allows remote authenticated users to execute script. The widget post_type setting accepts the widget-wpp array value and stores it without neutralizing script-capable markup before output. The attack requires high-level WordPress privileges; the stored markup executes in the WordPress origin when the affected widget state is rendered.

CVSS severity5.4
Medium
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Hector Cabrera WP Popular Posts 5.3.3 and earlier allows remote authenticated users to execute script. The widget post_type setting accepts the widget-wpp array value and stores it without neutralizing script-capable markup before output. The attack requires high-level WordPress privileges; the stored markup executes in the WordPress origin when the affected widget state is rendered.

The record

CVE
CVE-2021-36872
Published
Sep 23, 2021
Updated
Apr 28, 2026
Vendor
Hector Cabrera
Product
WP Popular Posts
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Sep 23, 2021CVE 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=5.3.3 <=5.3.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Hector Cabrera · WP Popular Postsversion=5.3.3 <=5.3.3

Published CVSS scores

5.5PatchstackCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
3.5NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NVDCVSS: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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Cross-site Scripting (XSS)
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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