Reported vulnerability
Speed Optimizer <= 7.8.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via Image Tag Attributes
Published 18 Aug 2026
Updated 19 Aug 2026
CVE-2026-15421
Compare your installed software with the affected versions below. Follow the source’s remediation guidance and test an available update after taking a backup. A database entry describes a reported issue; it does not establish whether a particular website has been compromised.
Does this affect my version?
Check your installed version against this advisory. This compares the report’s version ranges and does not scan your website.
Wordfence advisory
medium · CVSS 6.4The 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.
Severity vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Speed Optimizer – The All-In-One Performance-Boosting Plugin
- Software
- plugin · sg-cachepress
- Affected versions
- Start version unspecified, through 7.8.0
- Fix availability
- Fix available
- Fixed versions
- 7.8.1
Recommended action
Update to version 7.8.1, or a newer patched version
Further references (1)
Data sources and licences
Copyright 2012-2026 Defiant Inc.
Defiant hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute this software vulnerability information. Any copy of the software vulnerability information you make for such purposes is authorized provided that you include a hyperlink to this vulnerability record and reproduce Defiant's copyright designation and this license in any such copy.
Read licence termsCopyright 1999-2026 The MITRE Corporation
CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
Read licence termsSource: Wordfence
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Get help with this issueQuestions about this vulnerability
Which versions of Speed Optimizer – The All-In-One Performance-Boosting Plugin are affected?
Wordfence lists these affected versions: Start version unspecified, through 7.8.0. Use the version checker above to compare your installed release with this report.
Is a fix available for Speed Optimizer – The All-In-One Performance-Boosting Plugin?
Wordfence reports a fix for this issue in Speed Optimizer – The All-In-One Performance-Boosting Plugin. It lists these fixed versions: 7.8.1. Back up your website and test the recommended update before applying it to your live site.
Where can I find my installed plugin version?
In WordPress, open Plugins > Installed Plugins and find the version shown beneath the plugin name.
Does an affected version mean my website has been hacked?
An affected version means the installed release matches a vulnerability described in this report. It does not show whether anyone has exploited it on your website. The checker compares version numbers with stored reports; it does not inspect your website.
Other reports for the same product
These reports cover at least one of the same plugins, themes or WordPress core. Check each report’s affected versions separately.