diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 4691845bf815..9e050d034005 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -1332,6 +1332,21 @@ isert_recv_done(struct ib_cq *cq, struct ib_wc *wc)
 	ib_dma_sync_single_for_cpu(ib_dev, rx_desc->dma_addr,
 			ISER_RX_SIZE, DMA_FROM_DEVICE);
 
+	/*
+	 * The data segment length declared in the BHS is attacker controlled
+	 * and is used further down to read that many bytes out of the fixed
+	 * size receive descriptor, so it has to be checked against the number
+	 * of bytes that were actually received. Comparing without subtracting
+	 * also rejects PDUs shorter than the iSER and iSCSI headers, which
+	 * would otherwise be parsed out of stale descriptor contents.
+	 */
+	if (unlikely(wc->byte_len < ISER_HEADERS_LEN + ntoh24(hdr->dlength))) {
+		isert_err("PDU declares %u data bytes but only %u bytes were received\n",
+			  ntoh24(hdr->dlength), wc->byte_len);
+		iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
+		return;
+	}
+
 	isert_dbg("DMA: 0x%llx, iSCSI opcode: 0x%02x, ITT: 0x%08x, flags: 0x%02x dlen: %d\n",
 		 rx_desc->dma_addr, hdr->opcode, hdr->itt, hdr->flags,
 		 (int)(wc->byte_len - ISER_HEADERS_LEN));