# ShortPixel Adaptive Images – WebP, AVIF, CDN, Image Optimization <= 3.11.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via Image URLs

- **ID:** WPSEC-2026-3103
- **Plugin:** ShortPixel Adaptive Images – WebP, AVIF, CDN, Image Optimization (`shortpixel-adaptive-images`), https://wordpress.org/plugins/shortpixel-adaptive-images/
- **Affected versions:** all versions before 3.12.0
- **Fixed in:** 3.12.0 (Update to 3.12.0 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 2026-11-13)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/shortpixel-adaptive-images
- **Fix released:** 2026-11-12
- **Published:** 2026-11-13
- **URL:** https://wpsec.com/vuln/WPSEC-2026-3103/

## Description

The ShortPixel Adaptive Images plugin for WordPress is vulnerable to Stored Cross-Site Scripting via image and background image URLs in all versions up to, and including, 3.11.6 due to insufficient validation and output escaping of URLs that the plugin rewrites into CDN addresses and placeholder attributes. URLs still containing quotes or angle brackets after entity decoding were accepted and written back into the page, allowing them to break out of the attribute. 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.

## References

- https://wpsec.com/vuln/WPSEC-2026-3103/
- https://plugins.svn.wordpress.org/shortpixel-adaptive-images/tags/3.12.0/
- https://wordpress.org/plugins/shortpixel-adaptive-images/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-3103/

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.