CVE-2026-100159 Popup Box 6.4.1 - 6.4.2 - Unauthenticated Arbitrary Shortcode Execution via Client-IP / X-Forwarded-For HTTP Headers
Unauthenticated attackers can execute arbitrary shortcodes via HTTP headers if an admin uses a specific token in popup content, potentially reading data or executing code.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-100159?
CVE-2026-100159 is a medium-severity code injection vulnerability in ays-pro Popup Box – Create Countdown, Coupon, Video, Contact Form Popups, published on 16 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-94
Which versions are affected by CVE-2026-100159?
How do I fix CVE-2026-100159?
No fix has been published for CVE-2026-100159 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-100159 being exploited?
There is no known exploitation of CVE-2026-100159 in the wild and no public exploit code.
Sources
Also known as GHSA-5jv4-j9f2-3247.