diff --git a/pbs-config/src/network/parser.rs b/pbs-config/src/network/parser.rs
index e53543ba..2cff6587 100644
--- a/pbs-config/src/network/parser.rs
+++ b/pbs-config/src/network/parser.rs
@@ -384,8 +384,9 @@ impl<R: BufRead> NetworkParser<R> {
                 if mask.is_some() {
                     // address already has a mask  - ignore netmask
                 } else {
+                    use std::fmt::Write as _;
                     check_netmask(netmask, is_v6)?;
-                    cidr.push_str(&format!("/{}", netmask));
+                    let _ = write!(cidr, "/{}", netmask);
                 }
                 if is_v6 {
                     set_cidr_v6(interface, cidr)?;
diff --git a/proxmox-rest-server/src/worker_task.rs b/proxmox-rest-server/src/worker_task.rs
index a1eea832..44d81119 100644
--- a/proxmox-rest-server/src/worker_task.rs
+++ b/proxmox-rest-server/src/worker_task.rs
@@ -637,12 +637,9 @@ pub struct TaskListInfo {
 fn render_task_line(info: &TaskListInfo) -> String {
     let mut raw = String::new();
     if let Some(status) = &info.state {
-        raw.push_str(&format!(
-            "{} {:08X} {}\n",
-            info.upid_str,
-            status.endtime(),
-            status
-        ));
+        use std::fmt::Write as _;
+
+        let _ = writeln!(raw, "{} {:08X} {}", info.upid_str, status.endtime(), status);
     } else {
         raw.push_str(&info.upid_str);
         raw.push('\n');
diff --git a/src/api2/node/dns.rs b/src/api2/node/dns.rs
index 18cf680f..f45f5395 100644
--- a/src/api2/node/dns.rs
+++ b/src/api2/node/dns.rs
@@ -174,12 +174,13 @@ pub fn update_dns(
 
     let mut data = String::new();
 
+    use std::fmt::Write as _;
     if let Some(search) = config["search"].as_str() {
-        data.push_str(&format!("search {}\n", search));
+        let _ = writeln!(data, "search {}", search);
     }
     for opt in &["dns1", "dns2", "dns3"] {
         if let Some(server) = config[opt].as_str() {
-            data.push_str(&format!("nameserver {}\n", server));
+            let _ = writeln!(data, "nameserver {}", server);
         }
     }
     if let Some(options) = config["options"].as_str() {
diff --git a/src/server/email_notifications.rs b/src/server/email_notifications.rs
index 898bc8f3..f60acc64 100644
--- a/src/server/email_notifications.rs
+++ b/src/server/email_notifications.rs
@@ -476,21 +476,24 @@ pub fn send_load_media_email(
     to: &str,
     reason: Option<String>,
 ) -> Result<(), Error> {
+    use std::fmt::Write as _;
+
     let subject = format!("Load Media '{}' request for drive '{}'", label_text, drive);
 
     let mut text = String::new();
 
     if let Some(reason) = reason {
-        text.push_str(&format!(
+        let _ = write!(
+            text,
             "The drive has the wrong or no tape inserted. Error:\n{}\n\n",
             reason
-        ));
+        );
     }
 
     text.push_str("Please insert the requested media into the backup drive.\n\n");
 
-    text.push_str(&format!("Drive: {}\n", drive));
-    text.push_str(&format!("Media: {}\n", label_text));
+    let _ = writeln!(text, "Drive: {}", drive);
+    let _ = writeln!(text, "Media: {}", label_text);
 
     send_job_status_mail(to, &subject, &text)
 }