diff --git a/hw/audio/cs4231a.c b/hw/audio/cs4231a.c
index 06b44da869..eb9a45805b 100644
--- a/hw/audio/cs4231a.c
+++ b/hw/audio/cs4231a.c
@@ -682,6 +682,10 @@ static void cs4231a_realizefn (DeviceState *dev, Error **errp)
         return;
     }
 
+    if (s->irq >= ISA_NUM_IRQS) {
+        error_setg(errp, "Invalid IRQ %d (max %d)", s->irq, ISA_NUM_IRQS - 1);
+        return;
+    }
     s->pic = isa_bus_get_irq(bus, s->irq);
     k = ISADMA_GET_CLASS(s->isa_dma);
     k->register_channel(s->isa_dma, s->dma, cs_dma_read, s);