diff --git a/socketioxide/src/packet.rs b/socketioxide/src/packet.rs
index 3968775c..261414a9 100644
--- a/socketioxide/src/packet.rs
+++ b/socketioxide/src/packet.rs
@@ -445,19 +445,21 @@ impl<'a> TryFrom<Str> for Packet<'a> {
     fn try_from(value: Str) -> Result<Self, Self::Error> {
         let chars = value.as_bytes();
         // It is possible to parse the packet from a byte slice because separators are only ASCII
-        let mut i = 1;
         let index = (b'0'..=b'6')
             .contains(&chars[0])
             .then_some(chars[0])
             .ok_or(Error::InvalidPacketType)?;
 
         // Move the cursor to skip the payload count if it is a binary packet
-        if index == b'5' || index == b'6' {
-            while chars.get(i) != Some(&b'-') {
-                i += 1;
-            }
-            i += 1;
-        }
+        let mut i = if index == b'5' || index == b'6' {
+            chars
+                .iter()
+                .position(|x| *x == b'-')
+                .ok_or(Error::InvalidPacketType)?
+                + 1
+        } else {
+            1
+        };
 
         let start_index = i;
         // Custom nsps will start with a slash
@@ -919,4 +921,12 @@ mod test {
         let packet = Packet::bin_ack("/", json!("data"), vec![Bytes::from_static(&[1])], 54);
         assert_eq!(packet.get_size_hint(), 5);
     }
+
+    #[test]
+    fn packet_reject_invalid_binary_event() {
+        let payload = "5invalid".to_owned();
+        let err = Packet::try_from(payload).unwrap_err();
+
+        assert!(matches!(err, Error::InvalidPacketType));
+    }
 }