diff --git a/catalog/templates/_item_card.html b/catalog/templates/_item_card.html
index 05c980c1..7ef26b48 100644
--- a/catalog/templates/_item_card.html
+++ b/catalog/templates/_item_card.html
@@ -9,7 +9,9 @@
           {% if not hide_category %}<span class="category">[{{ item.category.label }}]</span>{% endif %}
           <span class="site-list">
             {% for res in item.external_resources.all %}
-              <a href="{{ res.url }}" class="{{ res.site_name }}">{{ res.site_label }}</a>
+              <a href="{{ res.url }}"
+                 class="{{ res.site_name }}"
+                 rel="noopener noreferrer">{{ res.site_label }}</a>
             {% endfor %}
           </span>
         </small>
diff --git a/catalog/templates/_item_card_metadata_base.html b/catalog/templates/_item_card_metadata_base.html
index 0b829c65..adb3be2a 100644
--- a/catalog/templates/_item_card_metadata_base.html
+++ b/catalog/templates/_item_card_metadata_base.html
@@ -15,7 +15,9 @@
       {% if not hide_category %}<span class="category">[{{ item.category.label }}]</span>{% endif %}
       <span class="site-list">
         {% for res in item.external_resources.all %}
-          <a href="{{ res.url }}" class="{{ res.site_name }}">{{ res.site_label }}</a>
+          <a href="{{ res.url }}"
+             class="{{ res.site_name }}"
+             rel="noopener noreferrer">{{ res.site_label }}</a>
         {% endfor %}
       </span>
     </small>
diff --git a/catalog/templates/_sidebar_edit.html b/catalog/templates/_sidebar_edit.html
index a6e7582a..6dc452c0 100644
--- a/catalog/templates/_sidebar_edit.html
+++ b/catalog/templates/_sidebar_edit.html
@@ -50,7 +50,7 @@
     {% for res in item.external_resources.all %}
       <details>
         <summary>
-          {% trans 'External website' %}: <a href="{{ res.url }}">{{ res.site_label }}</a>
+          {% trans 'External website' %}: <a href="{{ res.url }}" rel="noopener noreferrer">{{ res.site_label }}</a>
         </summary>
         <div class="grid">
           <form method="post"
diff --git a/catalog/templates/edition.html b/catalog/templates/edition.html
index 53998099..5e311f57 100644
--- a/catalog/templates/edition.html
+++ b/catalog/templates/edition.html
@@ -100,7 +100,7 @@
               <a href="{{ b.url }}">{{ b.display_title }}</a>
               <small class="title_deco">{{ b.title_deco }}</small>
               {% comment %} {% for res in b.external_resources.all %}
-              <a href="{{ res.url }}">
+              <a href="{{ res.url }}" rel="noopener noreferrer">
                 <span class="source-label source-label__{{ res.site_name }}">{{ res.site_name.label }}</span>
               </a>
               {% endfor %} {% endcomment %}