diff --git a/drivers/acpid/src/acpi/dmar/mod.rs b/drivers/acpid/src/acpi/dmar/mod.rs
--- a/drivers/acpid/src/acpi/dmar/mod.rs
+++ b/drivers/acpid/src/acpi/dmar/mod.rs
@@ -475,8 +475,12 @@ impl<'sdt> Iterator for DmarRawIter<'sdt> {
             .expect("expected a 2-byte slice to be convertible to [u8; 2]");
 
-        let ty = u16::from_ne_bytes(type_bytes);
-        let len = u16::from_ne_bytes(len_bytes);
+        let len = u16::from_ne_bytes(len_bytes) as usize;
+
+        if len < 4 {
+            return None;
+        }
+
+        let ty = u16::from_ne_bytes(type_bytes);
 
-        let len = usize::try_from(len).expect("expected u16 to fit within usize");
 
         if len > remainder.len() {