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