diff --git a/app/activitypub/util.py b/app/activitypub/util.py
index e55bc4cc..ba95c3c5 100644
--- a/app/activitypub/util.py
+++ b/app/activitypub/util.py
@@ -1833,7 +1833,7 @@ def update_post_from_activity(post: Post, request_json: dict):
     # Links
     old_url = post.url
     new_url = None
-    if 'attachment' in request_json['object'] and isinstance(request_json['object']['attachment'], list) and \
+    if 'attachment' in request_json['object'] and isinstance(request_json['object']['attachment'], list) and len(request_json['object']['attachment']) > 0 and \
             'type' in request_json['object']['attachment'][0]:
         if request_json['object']['attachment'][0]['type'] == 'Link':
             new_url = request_json['object']['attachment'][0]['href']              # Lemmy < 0.19.4
diff --git a/app/models.py b/app/models.py
index 41ac8040..1628a12a 100644
--- a/app/models.py
+++ b/app/models.py
@@ -1227,7 +1227,7 @@ class Post(db.Model):
                 if blocked_phrase in post.body:
                     return None
 
-        if 'attachment' in request_json['object'] and isinstance(request_json['object']['attachment'], list) and \
+        if 'attachment' in request_json['object'] and isinstance(request_json['object']['attachment'], list) and len(request_json['object']['attachment']) > 0 and \
                 'type' in request_json['object']['attachment'][0]:
             alt_text = None
             if request_json['object']['attachment'][0]['type'] == 'Link':