diff --git a/src/server.rs b/src/server.rs
index b644062..47c70de 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -479,8 +479,14 @@ impl Server {
         let tx = self.event_tx.clone();
         std::thread::spawn(move || {
             let _guard = Guard; // decrements even on panic
-            let ev = f();
-            let _ = tx.send(ev);
+            match std::panic::catch_unwind(std::panic::AssertUnwindSafe(f)) {
+                Ok(ev) => {
+                    let _ = tx.send(ev);
+                }
+                // a panic here can't reach the core (we don't know which Event to send);
+                // log it so a stuck request is diagnosable instead of silent.
+                Err(_) => eprintln!("[worker] a background crypto/http task panicked; its request was dropped"),
+            }
         });
         true
     }
diff --git a/src/socketengine.rs b/src/socketengine.rs
index 20b80c8..d1b455f 100644
--- a/src/socketengine.rs
+++ b/src/socketengine.rs
@@ -351,11 +351,25 @@ pub fn run_reactor(
                     }
                 }
                 Token(t) => {
+                    // isolate per-connection I/O: a panic framing one client's bytes
+                    // drops that client, never the reactor that serves all the others.
                     if event.is_readable() {
-                        read_conn(&mut poll, &mut conns, t, &core);
+                        let r = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+                            read_conn(&mut poll, &mut conns, t, &core)
+                        }));
+                        if r.is_err() {
+                            eprintln!("[reactor] recovered from a panic reading a socket; dropping that connection");
+                            close_conn(&mut poll, &mut conns, t, &core);
+                        }
                     }
                     if event.is_writable() && conns.contains_key(&t) {
-                        flush_conn(&mut poll, &mut conns, t, &core);
+                        let r = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+                            flush_conn(&mut poll, &mut conns, t, &core)
+                        }));
+                        if r.is_err() {
+                            eprintln!("[reactor] recovered from a panic writing a socket; dropping that connection");
+                            close_conn(&mut poll, &mut conns, t, &core);
+                        }
                     }
                 }
             }