Stored Cross-Site Scripting Vulnerability in Speed Optimizer Plugin by WordPress
CVE-2026-15421

6.4MEDIUM

Key Information:

Vendor

WordPress
Status
Speed Optimizer – The All-in-one Performance-boosting Plugin
Vendor
CVE Published:
19 August 2026

What is CVE-2026-15421?

The Speed Optimizer plugin for WordPress is susceptible to a stored cross-site scripting vulnerability that affects all versions up to and including 7.8.0. This flaw arises from inadequate input sanitization and output escaping, allowing authenticated attackers with contributor-level access and above to inject malicious web scripts into pages. Such scripts execute when an unsuspecting user accesses an affected page. This vulnerability is particularly exploitable if the site administrator has enabled the Lazy Load Media option within the plugin's settings.

Affected Version(s)

Speed Optimizer – The All-In-One Performance-Boosting Plugin 0 <= 7.8.0

References

https://www.wordfence.com/threat-intel/vulnerabilities/id...
https://plugins.trac.wordpress.org/browser/sg-cachepress/...
https://plugins.trac.wordpress.org/browser/sg-cachepress/...

CVSS V3.1

Score:
6.4
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

stealthcopter
.