diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9ec73de..3412cf5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Fixed
 
 - Don't ignore `Delete(Person)` verification errors if database error subtype is not `NotFound`.
+- Don't stop activity processing on invalid local mentions.
 
 ## [1.9.0] - 2023-01-08
 
diff --git a/src/activitypub/fetcher/helpers.rs b/src/activitypub/fetcher/helpers.rs
index a63088f..3c622d3 100644
--- a/src/activitypub/fetcher/helpers.rs
+++ b/src/activitypub/fetcher/helpers.rs
@@ -146,8 +146,10 @@ pub async fn get_or_import_profile_by_actor_address(
         &acct,
     ).await {
         Ok(profile) => profile,
-        Err(DatabaseError::NotFound(_)) => {
-            // TODO: don't fetch if address is local
+        Err(db_error @ DatabaseError::NotFound(_)) => {
+            if actor_address.hostname == instance.hostname() {
+                return Err(db_error.into());
+            };
             import_profile_by_actor_address(
                 db_client,
                 instance,
diff --git a/src/activitypub/handlers/create.rs b/src/activitypub/handlers/create.rs
index 376f130..8e6097a 100644
--- a/src/activitypub/handlers/create.rs
+++ b/src/activitypub/handlers/create.rs
@@ -20,6 +20,7 @@ use crate::activitypub::{
     vocabulary::*,
 };
 use crate::config::{Config, Instance};
+use crate::database::DatabaseError;
 use crate::errors::{ConversionError, ValidationError};
 use crate::models::attachments::queries::create_attachment;
 use crate::models::posts::{
@@ -275,8 +276,12 @@ pub async fn handle_note(
                         &actor_address,
                     ).await {
                         Ok(profile) => profile,
-                        Err(HandlerError::FetchError(error)) => {
+                        Err(error @ (
+                            HandlerError::FetchError(_) |
+                            HandlerError::DatabaseError(DatabaseError::NotFound(_))
+                        )) => {
                             // Ignore mention if fetcher fails
+                            // Ignore mention if local address is not valid
                             log::warn!(
                                 "failed to find mentioned profile {}: {}",
                                 actor_address,