dbcve.org
Deserialization of Untrusted DataWeakness · CWE-502

CVE-2024-4838

HIGH · 7.5 CVSS v3.1 Published 2024-05-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
81/100
Remediation priority · High
Remotely reachable Zero-click

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
The ConvertPlus plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 3.5.26 via deserialization of untrusted input from the 'settings_encoded' attribute of the 'smile_modal' shortcode. This makes it possible for authenticated attackers, with contributor-level access and above, to inject a PHP Object. No POP chain is present in the vulnerable plugin. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.

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

The ConvertPlus WordPress plugin is vulnerable to PHP Object Injection through the 'smile_modal' shortcode's 'settings_encoded' attribute, which deserializes untrusted input. Authenticated users with contributor-level access or higher can inject PHP objects. While no POP chain exists in the plugin itself, additional plugins or themes could provide one for exploitation.

MitigationUpdate ConvertPlus to version 3.5.27 or later to patch the deserialization vulnerability. If immediate patching is not feasible, audit contributor-level users and consider disabling the smile_modal shortcode until the update can be applied.

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

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
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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. Identify ConvertPlus plugin version
    Navigate to WordPress Admin > Plugins > Installed Plugins > ConvertPlus and view the Version field. Alternatively, check the main plugin file header in wp-content/plugins/convertplug/convertplug.php for the 'Version' comment.
    Affected if Version is lower than 3.5.27 (the shortcode will deserialize untrusted input)
  2. Detect if smile_modal shortcode is in use
    Search WordPress content database: query wp_posts for post_content containing '[smile_modal' using phpMyAdmin or WP-CLI: wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content LIKE '%smile_modal%' AND post_status='publish'"
    Affected if The shortcode is present in published content with a settings_encoded attribute containing serialized data
  3. Inspect the settings_encoded attribute value
    Examine any found smile_modal shortcode usage and decode the settings_encoded parameter (base64_decode). If it contains a serialized PHP object (O:... or a:...), this confirms the vulnerable pattern is present.
    Affected if The settings_encoded parameter contains serialized data that could be crafted as a PHP object
  4. Audit user roles with contributor-level access
    In WordPress Admin > Users, review all users assigned the Contributor, Author, Editor, or Administrator role. These roles can access the vulnerable shortcode.
    Affected if Any authenticated user with contributor-level or higher access exists in the system

You are affected if ConvertPlus is installed below version 3.5.27 AND the smile_modal shortcode with a settings_encoded attribute is in use by any contributor-level or higher user.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update ConvertPlus to version 3.5.27 or later to patch the deserialization vulnerability. If immediate patching is not feasible, audit contributor-level users and consider disabling the smile_modal shortcode until the update can be applied.

Recommended fix High confidence

ConvertPlus version 3.5.27 or later

  1. 1. Update the ConvertPlus plugin to version 3.5.27 or later via the WordPress admin dashboard under Plugins > All Plugins > ConvertPlus > Update Now
  2. 2. Alternatively, update via WordPress repository or contact the vendor for the latest version
  3. 3. Verify the update was successful by checking the plugin version in Plugins > Installed Plugins
  4. 4. Confirm that the 'smile_modal' shortcode no longer accepts untrusted serialized data in the 'settings_encoded' attribute

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

Have this fixed 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 help mitigating

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-2024-4838 in production — separate from our analysis above.

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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
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