# CVE-2026-39573: Select-Themes Mildhill PHP object injection

Source: https://junglewise.ai/threats/cve-2026-39573-select-themes-mildhill-php-object-injection  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-17. Updated: 2026-06-17  
License: CC BY 4.0 with a link back

CVE-2026-39573 · Severity: high · CVSS 8.1 · Published 2026-06-17

The Mildhill theme for WordPress is vulnerable to a security flaw that allows unauthorized users to inject malicious code into a website. This could lead to complete site takeover, data theft, or service disruption. Website owners should update the theme to version 1.6 immediately to protect their operations and customer data.

Vendors: [Select-Themes](https://junglewise.ai/threats/vendors/select-themes).

## Quick answers

**Is CVE-2026-39573 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-39573 being exploited in the wild.

**How severe is CVE-2026-39573?** High severity, with a CVSS score of 8.1, published 17 June 2026.

**Which products and versions are affected?** Select-Themes Mildhill <= 1.5.

**Is there a fix for CVE-2026-39573?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-39573 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-39573?** Check whether you run Select-Themes Mildhill at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A PHP Object Injection vulnerability exists in the Mildhill WordPress theme (versions <= 1.5) due to the unsafe deserialization of user-supplied data (CWE-502). An unauthenticated remote attacker can exploit this by sending specially crafted input to the application. If a suitable Property-Oriented Programming (POP) chain is present within the environment, the attacker could achieve remote code execution, perform SQL injection, or access sensitive files. The vulnerability is addressed in version 1.6.

## Affected products

- Select-Themes Mildhill <= 1.5

## Timeline

- 2026-02-12: other: Reported by Denver Jackson
- 2026-04-08: disclosed: Initial disclosure by Patchstack
- 2026-06-17: advisory: NVD publication date

## References

- [https://wordpress.org/themes](https://wordpress.org/themes)
- [https://patchstack.com/database/wordpress/theme/mildhill/vulnerability/wordpress-mildhill-theme-1-5-php-object-injection-vulnerability?_s_id=cve](https://patchstack.com/database/wordpress/theme/mildhill/vulnerability/wordpress-mildhill-theme-1-5-php-object-injection-vulnerability?_s_id=cve)