Description
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.
Published: 2026-08-19
Score: 6.4 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Fri, 21 Aug 2026 13:00:00 +0000

Type Values Removed Values Added
First Time appeared Siteground
Siteground speed Optimizer – The All-in-one Performance-boosting Plugin
Wordpress
Wordpress wordpress
Vendors & Products Siteground
Siteground speed Optimizer – The All-in-one Performance-boosting Plugin
Wordpress
Wordpress wordpress

Wed, 19 Aug 2026 02:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Speed Optimizer <= 7.8.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via Image Tag Attributes
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 6.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N'}


Subscriptions

Siteground Speed Optimizer – The All-in-one Performance-boosting Plugin
Wordpress Wordpress
cve-icon MITRE

Status: PUBLISHED

Assigner: Wordfence

Published:

Updated: 2026-08-20T15:36:47.771Z

Reserved: 2026-07-10T15:11:57.894Z

Link: CVE-2026-15421

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-08-19T02:16:12.677

Modified: 2026-08-20T16:17:08.303

Link: CVE-2026-15421

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-21T12:31:42Z

Weaknesses