diff --git a/db/patch-timeout.sql b/db/patch-timeout.sql
new file mode 100644
index 000000000..f25711201
--- /dev/null
+++ b/db/patch-timeout.sql
@@ -0,0 +1,7 @@
+-- You should not modify if this have pushed to Github, unless it does serious wrong with the db.
+BEGIN TRANSACTION;
+
+UPDATE monitor SET timeout = (interval * 0.8)
+WHERE timeout IS NULL OR timeout <= 0;
+
+COMMIT;
diff --git a/server/database.js b/server/database.js
index 29ab3b941..07a43a812 100644
--- a/server/database.js
+++ b/server/database.js
@@ -83,6 +83,7 @@ class Database {
         "patch-add-gamedig-given-port.sql": true,
         "patch-notification-config.sql": true,
         "patch-fix-kafka-producer-booleans.sql": true,
+        "patch-timeout.sql": true,
     };
 
     /**
diff --git a/server/model/monitor.js b/server/model/monitor.js
index 54a1972c4..194980a12 100644
--- a/server/model/monitor.js
+++ b/server/model/monitor.js
@@ -369,7 +369,7 @@ class Monitor extends BeanModel {
 
             // Runtime patch timeout if it is 0
             // See https://github.com/louislam/uptime-kuma/pull/3961#issuecomment-1804149144
-            if (this.timeout <= 0) {
+            if (!this.timeout || this.timeout <= 0) {
                 this.timeout = this.interval * 1000 * 0.8;
             }