diff --git a/ghost/admin/app/components/gh-koenig-editor-lexical.hbs b/ghost/admin/app/components/gh-koenig-editor-lexical.hbs
index 3ed24c5326..2919f96159 100644
--- a/ghost/admin/app/components/gh-koenig-editor-lexical.hbs
+++ b/ghost/admin/app/components/gh-koenig-editor-lexical.hbs
@@ -32,6 +32,7 @@
             {{on "blur" (fn (mut this.titleIsFocused) false)}}
             {{on "mouseover" (fn (mut this.titleIsHovered) true)}}
             {{on "mouseleave" (fn (mut this.titleIsHovered) false)}}
+            {{on "paste" this.cleanPastedTitle}}
             data-test-editor-title-input={{true}}
         />
 
@@ -61,4 +62,4 @@
             @postType={{@postType}}
         /> --}}
     </div>
-</div>
\ No newline at end of file
+</div>
diff --git a/ghost/admin/app/components/gh-koenig-editor-lexical.js b/ghost/admin/app/components/gh-koenig-editor-lexical.js
index 5736be4f3e..879f1d1092 100644
--- a/ghost/admin/app/components/gh-koenig-editor-lexical.js
+++ b/ghost/admin/app/components/gh-koenig-editor-lexical.js
@@ -56,6 +56,20 @@ export default class GhKoenigEditorReactComponent extends Component {
         this.args.onTitleChange?.(event.target.value);
     }
 
+    @action
+    cleanPastedTitle(event) {
+        const pastedText = (event.clipboardData || window.clipboardData).getData('text');
+
+        if (!pastedText) {
+            return;
+        }
+
+        event.preventDefault();
+
+        const cleanValue = pastedText.replace(/(\n|\r)+/g, ' ').trim();
+        document.execCommand('insertText', false, cleanValue);
+    }
+
     @action
     focusTitle() {
         this.titleElement.focus();
diff --git a/ghost/admin/app/components/gh-koenig-editor.hbs b/ghost/admin/app/components/gh-koenig-editor.hbs
index 32c4bf0a0d..a1a9f142ea 100644
--- a/ghost/admin/app/components/gh-koenig-editor.hbs
+++ b/ghost/admin/app/components/gh-koenig-editor.hbs
@@ -32,6 +32,7 @@
             {{on "blur" (fn (mut this.titleIsFocused) false)}}
             {{on "mouseover" (fn (mut this.titleIsHovered) true)}}
             {{on "mouseleave" (fn (mut this.titleIsHovered) false)}}
+            {{on "paste" this.cleanPastedTitle}}
             data-test-editor-title-input={{true}}
         />
 
@@ -56,4 +57,4 @@
             @postType={{@postType}}
         />
     </div>
-</div>
\ No newline at end of file
+</div>
diff --git a/ghost/admin/app/components/gh-koenig-editor.js b/ghost/admin/app/components/gh-koenig-editor.js
index e21a18427a..93f0ee6fee 100644
--- a/ghost/admin/app/components/gh-koenig-editor.js
+++ b/ghost/admin/app/components/gh-koenig-editor.js
@@ -43,6 +43,20 @@ export default class GhKoenigEditorComponent extends Component {
         this.args.onTitleChange?.(event.target.value);
     }
 
+    @action
+    cleanPastedTitle(event) {
+        const pastedText = (event.clipboardData || window.clipboardData).getData('text');
+
+        if (!pastedText) {
+            return;
+        }
+
+        event.preventDefault();
+
+        const cleanValue = pastedText.replace(/(\n|\r)+/g, ' ').trim();
+        document.execCommand('insertText', false, cleanValue);
+    }
+
     @action
     focusTitle() {
         this.titleElement.focus();
diff --git a/ghost/admin/app/services/slug-generator.js b/ghost/admin/app/services/slug-generator.js
index f6ab19ad3b..397340e075 100644
--- a/ghost/admin/app/services/slug-generator.js
+++ b/ghost/admin/app/services/slug-generator.js
@@ -1,6 +1,7 @@
 import RSVP from 'rsvp';
 import Service, {inject as service} from '@ember/service';
 import classic from 'ember-classic-decorator';
+import {slugify} from '@tryghost/string';
 
 const {resolve} = RSVP;
 
@@ -16,7 +17,8 @@ export default class SlugGeneratorService extends Service {
             return resolve('');
         }
 
-        url = this.get('ghostPaths.url').api('slugs', slugType, encodeURIComponent(textToSlugify));
+        // We already do a partial slugify at the client side to prevent issues with Pro returning a 404 page because of invalid (encoded) characters (a newline, %0A, for example)
+        url = this.get('ghostPaths.url').api('slugs', slugType, encodeURIComponent(slugify(textToSlugify)));
 
         return this.ajax.request(url).then((response) => {
             let [firstSlug] = response.slugs;
diff --git a/ghost/admin/tests/integration/services/slug-generator-test.js b/ghost/admin/tests/integration/services/slug-generator-test.js
index 29bbc8c869..2ac4961e34 100644
--- a/ghost/admin/tests/integration/services/slug-generator-test.js
+++ b/ghost/admin/tests/integration/services/slug-generator-test.js
@@ -42,7 +42,7 @@ describe('Integration: Service: slug-generator', function () {
 
     it('calls correct endpoint and returns correct data', function (done) {
         let rawSlug = 'a test post';
-        stubSlugEndpoint(server, 'post', rawSlug);
+        stubSlugEndpoint(server, 'post', 'a-test-post');
 
         let service = this.owner.lookup('service:slug-generator');