Reported vulnerability

Popup Box 6.4.1 - 6.4.2 - Unauthenticated Arbitrary Shortcode Execution via Client-IP / X-Forwarded-For HTTP Headers

Published 15 Oct 2026

Updated 16 Oct 2026

CVE-2026-100159

Compare your installed software with the affected versions below. Follow the source’s remediation guidance and test an available update after taking a backup. A database entry describes a reported issue; it does not establish whether a particular website has been compromised.

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Wordfence advisory

medium · CVSS 4.8

The Popup Box plugin for WordPress is vulnerable to Arbitrary Shortcode Execution in versions 6.4.1 to 6.4.2. This is due to the ays_popup_get_user_ip() function reading the client-controlled Client-IP / X-Forwarded-For / Forwarded / X-Forwarded / Forwarded-For request headers, sanitizing them only with sanitize_text_field() (which does not strip the bracket, quote, space, or '=' characters used by shortcode syntax), substituting the value into a popup body wherever the %%user_ip_address%% token appears (a raw str_replace with no escaping in Ays_Pb_Data::replace_message_variables()), and then passing the resulting body to do_shortcode() in Ays_Pb_Public::ays_autoembed() at output on the wp_footer hook. This makes it possible for unauthenticated attackers to execute arbitrary registered shortcodes with attacker-supplied attributes on the server whenever an administrator has added the %%user_ip_address%% token to a popup's Custom Content body, which can be leveraged to read arbitrary data or perform other actions exposed by shortcodes installed on the site.

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

Popup Box – Create Countdown, Coupon, Video, Contact Form Popups

Software: plugin · ays-popup-box
Affected versions: From 6.4.1, through 6.4.2
Fix availability: Fix available
Fixed versions: 6.4.3

Recommended action

Update to version 6.4.3, or a newer patched version

Further references (1)

wordfence.com/threat-intel/vulnerabilities/id/535c4796-d1aa-4cd1-922e-f9dcf216f76d?source=api-prod

Data sources and licences

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CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

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Source: Wordfence

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Questions about this vulnerability

Which versions of Popup Box – Create Countdown, Coupon, Video, Contact Form Popups are affected?

Wordfence lists these affected versions: From 6.4.1, through 6.4.2. Use the version checker above to compare your installed release with this report.

Is a fix available for Popup Box – Create Countdown, Coupon, Video, Contact Form Popups?

Wordfence reports a fix for this issue in Popup Box – Create Countdown, Coupon, Video, Contact Form Popups. It lists these fixed versions: 6.4.3. Back up your website and test the recommended update before applying it to your live site.

Where can I find my installed plugin version?

In WordPress, open Plugins > Installed Plugins and find the version shown beneath the plugin name.

Does an affected version mean my website has been hacked?

An affected version means the installed release matches a vulnerability described in this report. It does not show whether anyone has exploited it on your website. The checker compares version numbers with stored reports; it does not inspect your website.

These reports cover at least one of the same plugins, themes or WordPress core. Check each report’s affected versions separately.

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