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Wordpress Popular PostsWordPress extension · Wordpress Popular Posts Project

CVE-2021-36872

MEDIUM · 5.4 CVSS v3.1 Published 2021-09-23
Fix available
A fix is available. Upgrade to after 5.3.3 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Authenticated Persistent Cross-Site Scripting (XSS) vulnerability in WordPress Popular Posts plugin (versions <= 5.3.3). Vulnerable at &widget-wpp[2][post_type].

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Authenticated users with widget configuration access can inject malicious JavaScript via the widget-wpp[post_type] parameter in WordPress Popular Posts plugin versions 5.3.3 and below. The post_type value is not properly sanitized before being stored and rendered in the frontend, allowing persistent XSS execution when the popular posts widget is displayed.

MitigationUpdate WordPress Popular Posts plugin to version newer than 5.3.3. If immediate update is not possible, restrict widget configuration access to only trusted administrator-level users until the patch can be applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Wordpress Popular PostsWordPress extension
Affected:<= 5.3.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if WordPress Popular Posts plugin is installed
    In the WordPress admin dashboard, go to Plugins > Installed Plugins and look for 'WordPress Popular Posts' in the list. Note whether it appears as active or inactive.
    Affected if The plugin is installed and active
  2. Determine the installed plugin version
    In the Plugins list, click on 'WordPress Popular Posts' to view the plugin details. The version number is displayed in the plugin metadata.
    Affected if The version listed is 5.3.3 or any version lower (for example, 5.3.2, 5.3.1, 5.3.0, etc.)
  3. Check for existing widget configurations using post_type
    In the WordPress admin, go to Appearance > Widgets. Look for any 'WordPress Popular Posts' widgets that have been added to sidebars. Expand each widget instance and check if the 'Post type(s)' field contains a custom value.
    Affected if A WordPress Popular Posts widget is active and the Post type field contains a manually entered or non-default value that may have been injected
  4. Verify user access to widget configuration
    In the WordPress admin, go to Users > All Users and review which user roles exist. Additionally, check if any non-administrator users have access to the Widgets admin page (Appearance > Widgets) by examining role capabilities.
    Affected if Non-administrator users (such as Editors or Authors) have access to configure widgets

A user is affected if the WordPress Popular Posts plugin version is 5.3.3 or lower AND the site has active widgets using custom post_type values OR non-admin users can configure widgets.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 5.3.3
Interim mitigation

Update WordPress Popular Posts plugin to version newer than 5.3.3. If immediate update is not possible, restrict widget configuration access to only trusted administrator-level users until the patch can be applied.

Recommended fix Moderate confidence

WordPress Popular Posts version > 5.3.4 (latest stable release)

  1. 1. Backup your WordPress database and files before making any changes.
  2. 2. Navigate to your WordPress admin dashboard > Plugins section.
  3. 3. Locate 'WordPress Popular Posts' plugin in the installed plugins list.
  4. 4. Click 'Update now' if an update is available, or manually download the latest version from the WordPress plugin repository.
  5. 5. Verify the update was successful by checking the plugin version is greater than 5.3.3.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Wordpress Popular Posts Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-36872 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data