# Speed Booster Pack <= 4.5.9.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via Image Attributes

- **ID:** WPSEC-2026-2736
- **Plugin:** Speed Booster Pack ⚡ PageSpeed Optimization Suite (`speed-booster-pack`), https://wordpress.org/plugins/speed-booster-pack/
- **Affected versions:** from 3.8.5 before 4.5.9.2
- **Fixed in:** 4.5.9.2 (Update to 4.5.9.2 or later.)
- **Severity:** Medium 6.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N)
- **Weakness:** CWE-79
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-11-08)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/speed-booster-pack
- **Fix released:** 2026-11-07
- **Published:** 2026-11-08
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2736/

## Description

The Speed Booster Pack ⚡ PageSpeed Optimization Suite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via image, source and iframe attributes in post content in all versions up to, and including, 4.5.9.1. This is due to the lazy-load output rewriting. It matches the first ' src=' text anywhere in a tag, including inside another attribute value such as alt text, and inserts a double-quoted placeholder there. This closes the surrounding double-quoted attribute, so text that passed content filtering inside the attribute becomes live attributes such as event handlers. 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 while lazy loading is enabled.

## References

- https://wpsec.com/vuln/WPSEC-2026-2736/
- https://plugins.svn.wordpress.org/speed-booster-pack/tags/4.5.9.2/
- https://wordpress.org/plugins/speed-booster-pack/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2736/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.