CVE-2026-15421 PUBLISHED

Speed Optimizer <= 7.8.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via Image Tag Attributes

Assigner: Wordfence
Reserved: 10.07.2026 Published: 19.08.2026 Updated: 19.08.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
CVSS Score: 6.4

Product Status

Vendor siteground
Product Speed Optimizer – The All-In-One Performance-Boosting Plugin
Versions Default: unaffected
  • affected from 0 to 7.8.0 (incl.)

Credits

  • stealthcopter finder

References

Problem Types

  • CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE