diff --git a/src/main/Main.js b/src/main/Main.js
index 329052798..74004a252 100644
--- a/src/main/Main.js
+++ b/src/main/Main.js
@@ -207,6 +207,7 @@ var Main = {
     if (
       /\.4chan(?:nel)?\.org$/.test(location.hostname) &&
       !SW.yotsuba.regexp.pass.test(location.href) &&
+      !SW.yotsuba.regexp.captcha.test(location.href) &&
       !$$('script:not([src])', d).filter(s => /this\[/.test(s.textContent)).length
     ) {
       ($.getSync || $.get)({'jsWhitelist': Conf['jsWhitelist']}, ({jsWhitelist}) => $.addCSP(`script-src ${jsWhitelist.replace(/^#.*$/mg, '').replace(/[\s;]+/g, ' ').trim()}`));
diff --git a/src/site/SW.yotsuba.tsx b/src/site/SW.yotsuba.tsx
index 1331b5a22..a1475aa1c 100644
--- a/src/site/SW.yotsuba.tsx
+++ b/src/site/SW.yotsuba.tsx
@@ -139,7 +139,9 @@ $\
     quotelinkHTML:
       /<a [^>]*\bhref="(?:(?:\/\/boards\.4chan(?:nel)?\.org)?\/([^\/]+)\/thread\/)?(\d+)?(?:#p(\d+))?"/g,
     pass:
-      /^https?:\/\/www\.4chan(?:nel)?\.org\/+pass(?:$|[?#])/
+      /^https?:\/\/www\.4chan(?:nel)?\.org\/+pass(?:$|[?#])/,
+    captcha:
+      /^https?:\/\/sys\.4chan(?:nel)?\.org\/+captcha(?:$|[?#])/,
   },
 
   bgColoredEl() {