# CVE-2026-111737: Speed Optimizer WordPress plugin stored XSS in settings

Source: https://junglewise.ai/threats/cve-2026-111737-the-speed-optimizer-wordpress-plugin-before-7-8-5-does-not  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-23. Updated: 2026-10-23  
License: CC BY 4.0 with a link back

CVE-2026-111737 · Severity: info · Published 2026-10-23

The Speed Optimizer WordPress plugin for website performance optimization fails to properly sanitize and escape certain configuration settings before displaying them on web pages. This allows site administrators to inject malicious scripts that execute in the browsers of visitors viewing the website, potentially leading to data theft, account hijacking, or malware distribution.

Technologies: [SiteGround Speed Optimizer](https://junglewise.ai/threats/technologies/speed-optimizer). Vendors: [SiteGround](https://junglewise.ai/threats/vendors/siteground).

## Quick answers

**Is CVE-2026-111737 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-111737 being exploited in the wild.

**How severe is CVE-2026-111737?** Informational severity, published 23 October 2026.

**Which products and versions are affected?** SiteGround Speed Optimizer before 7.8.5.

**Is there a fix for CVE-2026-111737?** Yes: fixed in 7.8.5. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-111737 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-111737?** Check whether you run SiteGround Speed Optimizer 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.

## How to fix

- Fixed in 7.8.5

## Technical details

The vulnerability is a stored cross-site scripting (XSS) flaw in DNS Prefetch and Font Preload URL list settings that are output unsanitized in the HTML head section of front-end pages. An authenticated attacker with admin-level privileges can inject arbitrary JavaScript through plugin settings, and the payload persists and executes for all site visitors. This occurs even in multisite WordPress installations where the unfiltered_html capability is otherwise restricted.

## Affected products

- SiteGround Speed Optimizer before 7.8.5

## Timeline

- 2026-10-23: disclosed
- 2026-10-21: advisory

## References

- [https://wpscan.com/vulnerability/308b6173-139d-4940-869d-c9ff1e83c323/](https://wpscan.com/vulnerability/308b6173-139d-4940-869d-c9ff1e83c323/)

## Related threats

- [Speed Optimizer plugin privilege escalation in network option handling](https://junglewise.ai/threats/cve-2026-111738-the-speed-optimizer-wordpress-plugin-before-7-8-5-does-not)
- [Multiple WordPress Plugins Stored XSS in HTML Minification](https://junglewise.ai/threats/cve-2026-3220-multiple-wordpress-plugins-stored-xss-in-html-minification)