Hummingbird Performance – Cache & Page Speed Optimization for Core Web Vitals | Critical CSS | Minify CSS | Defer CSS Javascript | CDN に脆弱性 — CVE-2026-83627
いま何をすべきか
Hummingbird Performance – Cache & Page Speed Optimization for Core Web Vitals | Critical CSS | Minify CSS | Defer CSS Javascript | CDN を 3.21.1 以降に更新してください。
影響を受けるバージョン
- 3.21.0 以下のすべて
対象: プラグイン「Hummingbird Performance – Cache & Page Speed Optimization for Core Web Vitals | Critical CSS | Minify CSS | Defer CSS Javascript | CDN」（hummingbird-performance）
何が起きるのか
The Hummingbird – Speed Optimization, Caching, Minify, Compress & CDN plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 3.21.0 via the log_msg() function in core/modules/class-page-cache.php. The page-cache debug log is written to wp-content/wphb-logs/page-caching-log.php, a directly web-accessible PHP file that is supposed to be protected by a leading '<?php die(); ?>' header. That header is guarded by class_exists( 'Filesystem' ), which can never match because class_exists() resolves string arguments in the global namespace while the class is Hummingbird\Core\Filesystem; when the log is created during a front-end request the header is therefore omitted entirely. get_cookies() then writes the raw name of any cookie matching the wphb_cache_ prefix into that file without sanitization. This makes it possible for unauthenticated attackers to write arbitrary PHP into the log file with a single anonymous request and execute it by requesting the file directly, resulting in full remote code execution. Exploitation requires the site administrator to have enabled Page Caching with the Debug Log option (non-default), and the log file to be created during a front-end request — a state reached by the plugin's own 'Clear logs' action, any cache flush, or unattended via the plugin's daily log-rotation cron, which can strip the protective header from an existing log file.
ここから先の選択肢
1. 自分たちで対応する
更新の手順、バックアップの取り方、壊れたときの戻し方をまとめています。
2. いまの制作会社・保守業者に頼む
Hummingbird Performance – Cache & Page Speed Optimization for Core Web Vitals | Critical CSS | Minify CSS | Defer CSS Javascript | CDN を使っているかどうかを含めて確認を依頼してください。 無料診断を実行すると、そのまま渡せる依頼文を作れます。
3. 相談先がない・自分では難しい
連絡が取れる相手がいない、管理画面に入れない、侵入された疑いがある。 そうした場合はご相談ください。