CVE-2026-15421
Speed Optimizer <= 7.8.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via Image Tag Attributes
The Speed Optimizer – The All-In-One Performance-Boosting Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Image Tag Attributes in all versions up to, and including, 7.8.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This is only exploitable when the site administrator has enabled the Lazy Load Media option in the plugin settings.
| CWE | CWE-79 |
| Vendor | siteground |
| Product | speed optimizer – the all-in-one performance-boosting plugin |
| Published | Aug 19, 2026 |
Get instant alerts for siteground speed optimizer – the all-in-one performance-boosting plugin
Be the first to know when new medium vulnerabilities affecting siteground speed optimizer – the all-in-one performance-boosting plugin are published — delivered to Slack, Telegram or Discord.
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N