CVE-2026-87741 ConvertPlus <= 3.6.3 - Authenticated (Subscriber+) PHP Object Injection via 'style' Parameter
Authenticated attackers can inject PHP objects via the style parameter, potentially leading to code execution or data access if a POP chain exists.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-87741?
CVE-2026-87741 is a high-severity unsafe deserialization vulnerability in Brainstorm Force ConvertPlus, published on 28 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The ConvertPlus plugin for WordPress is vulnerable to Deserialization of Untrusted Data in all versions up to, and including, 3.6.3 via the style parameter of the cp_display_preview_modal AJAX action. The vulnerability exists because the action's nonce guard is gated behind an isset() check and fails open when the cp_admin_page_nonce parameter is omitted entirely, no capability check is performed on the callback, and sanitize_text_field() — applied to the $style value before it is concatenated directly into a shortcode string evaluated by do_shortcode() — does not strip shortcode delimiters, allowing an attacker to inject a second, fully attacker-controlled [smile_modal] invocation that causes smile_modal_popup() to pass attacker-supplied base64-decoded bytes to maybe_unserialize() with no allowed_classes restriction. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject a PHP object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present.
Weakness: CWE-78
Which versions are affected by CVE-2026-87741?
How do I fix CVE-2026-87741?
No fix has been published for CVE-2026-87741 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-87741 being exploited?
There is no known exploitation of CVE-2026-87741 in the wild and no public exploit code.
Sources
Also known as GHSA-3h53-mhw6-2896.