CVE-2026-15421 json
Speed Optimizer <= 7.8.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via Image Tag Attributes
published 2026-08-19 2 mo ago modified 2026-10-22 18 d ago also EUVD-2026-62219
- cvss
- 6.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 35%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
Affected products
- siteground Speed Optimizer – The All-In-One Performance-Boosting Plugin
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/2626ad96-4346-4564-b6bd-0c226bd8dfd4?source=cve
- plugins.trac.wordpress.org /browser/sg-cachepress/tags/7.8.0/core/Lazy_Load/Lazy_Load_Images.php#L31
- plugins.trac.wordpress.org /browser/sg-cachepress/tags/7.8.0/core/Lazy_Load/Abstract_Lazy_Load.php#L109
- plugins.trac.wordpress.org /browser/sg-cachepress/tags/7.8.0/core/Lazy_Load/Lazy_Load.php#L39
- plugins.trac.wordpress.org /browser/sg-cachepress/tags/7.7.11/core/Lazy_Load/Lazy_Load_Images.php#L31
- plugins.trac.wordpress.org /browser/sg-cachepress/tags/7.7.11/core/Lazy_Load/Abstract_Lazy_Load.php#L109
- plugins.trac.wordpress.org /browser/sg-cachepress/tags/7.7.11/core/Lazy_Load/Lazy_Load.php#L39
- plugins.trac.wordpress.org /changeset?reponame=&new=3642965%40sg-cachepress%2Ftags%2F7.8.1&old=3581843%40sg-cachepress%2Ftags%2F7.8.0
- plugins.trac.wordpress.org /changeset?old_path=%2Fsg-cachepress/tags/7.8.0&new_path=%2Fsg-cachepress/tags/7.8.1
Sources
- CVE List CVE-2026-15421
- NVD CVE-2026-15421
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.