diff --git a/sys/dev/disk/ahci/ahci_cam.c b/sys/dev/disk/ahci/ahci_cam.c
--- a/sys/dev/disk/ahci/ahci_cam.c
+++ b/sys/dev/disk/ahci/ahci_cam.c
@@ -1129,9 +1129,14 @@
 		
 		/*
 		 * Use the vendor specific area to set the TRIM status
-		 * for scsi_da
+		 * for scsi_da.  The short Domain Validation inquiry buffer
+		 * (e.g. SID_ADDITIONAL_LENGTH+5 bytes) does not extend past
+		 * vendor_specific1, so make sure we have room before writing
+		 * to avoid corrupting the adjacent slab object.
 		 */
-		if (at->at_identify.support_dsm) {
+		if (at->at_identify.support_dsm &&
+		    rdata_len >= offsetof(struct scsi_inquiry_data,
+					  vendor_specific1) + 2) {
 			rdata->inquiry_data.vendor_specific1[0] =
 			    at->at_identify.support_dsm &ATA_SUPPORT_DSM_TRIM;
 			rdata->inquiry_data.vendor_specific1[1] =