SQL Security :: HTML Styles Getting Added With Actual Database Value

In addition to the column values, we are getting the below tag added throughout the table. It happens specifically to the columns with data type nvarchar and varchar and length >=100. We have 5 numbers of database but it happens only in one specific database. We doubt it to be sql injection but not sure how it happens. The impact is very severe on our clients. how to find the root cause. In that html tag have the url:...

Wilhite</title><style>.alwi{clip:rect(483px,auto,auto,427px);}</style><div
Blunt</title><style>.alwi{clip:rect(483px,auto,auto,427px);}</style><div>
Duran</title><style>.alwi{clip:rect(483px,auto,auto,427px);}</style><div>
Neiwert</title><style>.alwi{clip:rect(483px,auto,auto,427px);}</style><div>
Gerard</title><style>.alwi{clip:rect(483px,auto,auto,427px);}</style><div>
Hrnandez</title><style>.alwi{clip:rect(483px,auto,auto,427px);}</style><div class
Hernandez</title><style>.alwi{clip:rect(483px,auto,auto,427px);}</style><div class

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