Brainstorm Force ConvertPlus Plugin up to 3.6.3 on WordPress cp_display_preview_modal maybe_unserialize style deserialization

Summaryinfo

A vulnerability, which was classified as critical, was found in Brainstorm Force ConvertPlus Plugin up to 3.6.3. Affected is the function maybe_unserialize of the component cp_display_preview_modal. The manipulation of the argument style results in deserialization. This vulnerability was named CVE-2026-87741. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, was found in Brainstorm Force ConvertPlus Plugin up to 3.6.3. Affected is the function maybe_unserialize of the component cp_display_preview_modal. The manipulation of the argument style with an unknown input leads to a deserialization vulnerability. CWE is classifying the issue as CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at wordfence.com. This vulnerability is traded as CVE-2026-87741 since 09/09/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/28/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• WordPress Plugin

Vendor

• Brainstorm Force

Name

• ConvertPlus Plugin

Version

• 3.6.0
• 3.6.1
• 3.6.2
• 3.6.3

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CPE 2.2info

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