# Hummingbird – Speed Optimization, Caching, Minify, Compress & CDN <= 3.21.2 - Authenticated (Author+) Missing Authorization to Asset Optimization Settings Update and CDN Toggle

- **ID:** WPSEC-2026-2453
- **Plugin:** Hummingbird Performance – Cache & Page Speed Optimization for Core Web Vitals | Critical CSS | Minify CSS | Defer CSS Javascript | CDN (`hummingbird-performance`), https://wordpress.org/plugins/hummingbird-performance/
- **Affected versions:** from 3.4.0 before 4.0.0
- **Fixed in:** 4.0.0 (Update to 4.0.0 or later.)
- **Severity:** Medium 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N)
- **Weakness:** CWE-862
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-11-04)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/hummingbird-performance
- **Fix released:** 2026-11-03
- **Published:** 2026-11-04
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2453/

## Description

The Hummingbird Performance plugin for WordPress is vulnerable to unauthorized modification of data via the wphb_react_minify_manual_save_settings and wphb_react_minify_toggle_cdn AJAX actions in all versions up to, and including, 3.21.2, due to a missing capability check on the minify_manual_save_settings() and minify_toggle_cdn() functions, which only verify the 'wphb-fetch' nonce. That nonce is also printed in the block editor for published posts. This makes it possible for authenticated attackers with Author-level access and above to overwrite the plugin's manual Asset Optimization settings, such as per-file minify, combine, defer and don't-load options, and to turn the CDN on or off, which also clears the minified asset files.

## References

- https://wpsec.com/vuln/WPSEC-2026-2453/
- https://plugins.svn.wordpress.org/hummingbird-performance/tags/4.0.0/
- https://wordpress.org/plugins/hummingbird-performance/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2453/

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.