Index: /trunk/src/VBox/Devices/Storage/DevAHCI.cpp
===================================================================
--- /trunk/src/VBox/Devices/Storage/DevAHCI.cpp	(revision 53762)
+++ /trunk/src/VBox/Devices/Storage/DevAHCI.cpp	(revision 53763)
@@ -4172,5 +4172,5 @@
     int format = pAhciReq->aATAPICmd[7];
 
-    uint16_t max_len = ataBE2H_U16(&pAhciReq->aATAPICmd[8]);
+    uint16_t max_len = RT_MIN(ataBE2H_U16(&pAhciReq->aATAPICmd[8]), sizeof(aBuf));
 
     memset(buf, 0, max_len);