diff --git a/lib/hexo/validate_config.ts b/lib/hexo/validate_config.ts
index c7ca6477bd..73f97dede3 100644
--- a/lib/hexo/validate_config.ts
+++ b/lib/hexo/validate_config.ts
@@ -1,3 +1,4 @@
+import assert from 'assert';
 import type Hexo from './index';
 
 export = (ctx: Hexo): void => {
@@ -12,6 +13,8 @@ export = (ctx: Hexo): void => {
   try {
     // eslint-disable-next-line no-new
     new URL(config.url);
+    // eslint-disable-next-line no-new
+    assert(new URL(config.url).protocol.startsWith('http'));
   } catch {
     throw new TypeError('Invalid config detected: "url" should be a valid URL!');
   }
diff --git a/lib/plugins/filter/after_render/external_link.ts b/lib/plugins/filter/after_render/external_link.ts
index 7a0168d842..411502fc17 100644
--- a/lib/plugins/filter/after_render/external_link.ts
+++ b/lib/plugins/filter/after_render/external_link.ts
@@ -1,5 +1,5 @@
 import { isExternalLink } from 'hexo-util';
-import Hexo from '../../../hexo';
+import type Hexo from '../../../hexo';
 
 let EXTERNAL_LINK_SITE_ENABLED = true;
 const rATag = /<a(?:\s+?|\s+?[^<>]+?\s+?)href=["']((?:https?:|\/\/)[^<>"']+)["'][^<>]*>/gi;
@@ -7,6 +7,10 @@ const rTargetAttr = /target=/i;
 const rRelAttr = /rel=/i;
 const rRelStrAttr = /rel=["']([^<>"']*)["']/i;
 
+const addNoopener = (relStr: string, rel: string) => {
+  return rel.includes('noopenner') ? relStr : `rel="${rel} noopener"`;
+};
+
 function externalLinkFilter(this: Hexo, data: string): string {
   if (!EXTERNAL_LINK_SITE_ENABLED) return;
 
@@ -17,18 +21,30 @@ function externalLinkFilter(this: Hexo, data: string): string {
     return;
   }
 
-  return data.replace(rATag, (str, href) => {
-    if (!isExternalLink(href, url, external_link.exclude as any) || rTargetAttr.test(str)) return str;
+  let result = '';
+  let lastIndex = 0;
+  let match;
+
+  while ((match = rATag.exec(data)) !== null) {
+    result += data.slice(lastIndex, match.index);
 
-    if (rRelAttr.test(str)) {
-      str = str.replace(rRelStrAttr, (relStr, rel) => {
-        return rel.includes('noopenner') ? relStr : `rel="${rel} noopener"`;
-      });
-      return str.replace('href=', 'target="_blank" href=');
+    const str = match[0];
+    const href = match[1];
+
+    if (!isExternalLink(href, url, external_link.exclude as any) || rTargetAttr.test(str)) {
+      result += str;
+    } else {
+      if (rRelAttr.test(str)) {
+        result += str.replace(rRelStrAttr, addNoopener).replace('href=', 'target="_blank" href=');
+      } else {
+        result += str.replace('href=', 'target="_blank" rel="noopener" href=');
+      }
     }
+    lastIndex = rATag.lastIndex;
+  }
+  result += data.slice(lastIndex);
 
-    return str.replace('href=', 'target="_blank" rel="noopener" href=');
-  });
+  return result;
 }
 
 export = externalLinkFilter;
diff --git a/package.json b/package.json
index a2bd0843db..e2b76338bd 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,6 @@
     "build": "tsc -b",
     "clean": "tsc -b --clean",
     "eslint": "eslint lib test",
-    "pretest": "npm run clean && npm run build",
     "test": "mocha test/scripts/**/*.ts --require ts-node/register",
     "test-cov": "c8 --reporter=lcovonly npm test -- --no-parallel",
     "prepare": "husky"
diff --git a/test/scripts/box/file.ts b/test/scripts/box/file.ts
index edb485d812..3e3f65b5c4 100644
--- a/test/scripts/box/file.ts
+++ b/test/scripts/box/file.ts
@@ -38,7 +38,10 @@ describe('File', () => {
     params: {foo: 'bar'}
   });
 
-  before(async () => {
+  // NOTE: Do not use `arrow function` here.
+  //       See https://mochajs.org/#arrow-functions
+  before(async function() {
+    this.timeout(20000);
     await Promise.all([
       writeFile(file.source, body),
       hexo.init()
diff --git a/test/scripts/hexo/validate_config.ts b/test/scripts/hexo/validate_config.ts
index c414c2a68d..f64d43a22a 100644
--- a/test/scripts/hexo/validate_config.ts
+++ b/test/scripts/hexo/validate_config.ts
@@ -54,6 +54,20 @@ describe('Validate config', () => {
     }
   });
 
+
+  it('config.url - not start with xx://', () => {
+    // @ts-ignore
+    hexo.config.url = 'localhost:4000';
+
+    try {
+      validateConfig(hexo);
+      should.fail();
+    } catch (e) {
+      e.name.should.eql('TypeError');
+      e.message.should.eql('Invalid config detected: "url" should be a valid URL!');
+    }
+  });
+
   // #4510
   it('config.url - slash', () => {
     hexo.config.url = '/';