diff --git a/hw/eepro100.c b/hw/eepro100.c
index 89987d7fd1..f1a9310a67 100644
--- a/hw/eepro100.c
+++ b/hw/eepro100.c
@@ -537,12 +537,12 @@ static char *regname(uint32_t addr)
     if (addr < PCI_IO_SIZE) {
         const char *r = reg[addr / 4];
         if (r != 0) {
-            sprintf(buf, "%s+%u", r, addr % 4);
+            snprintf(buf, sizeof(buf), "%s+%u", r, addr % 4);
         } else {
-            sprintf(buf, "0x%02x", addr);
+            snprintf(buf, sizeof(buf), "0x%02x", addr);
         }
     } else {
-        sprintf(buf, "??? 0x%08x", addr);
+        snprintf(buf, sizeof(buf), "??? 0x%08x", addr);
     }
     return buf;
 }