ConvertPlus <= 3.6.3 - Authenticated (Subscriber+) PHP Object Injection via 'style' Parameter
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | ConvertPlus | <= 3.6.3 | 3.6.4 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-78- Platform
- WordPress
- Package
ConvertPlus- Disclosed
- 28.09.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
Wordfence Intelligence - 286b4dde-974d-4bb5-8a7e-57c849beaab1 - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: ConvertPlus
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 7
- First → latest
- 05.2019 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 5
- Medium 1
Disclosures per year
- 2019: 2
- 2020: 0
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 3
- 2025: 1
- 2026: 1
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ConvertPlus <= 3.6.3 - Authenticated (Subscriber+) PHP Object Injection via 'style' Parameter this entry
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