diff --git a/lib/krb5/fast.c b/lib/krb5/fast.c
index 5e4875c6c..7da456ce6 100644
--- a/lib/krb5/fast.c
+++ b/lib/krb5/fast.c
@@ -854,7 +854,7 @@ krb5_error_code
 _krb5_fast_anon_pkinit_step(krb5_context context,
 			    krb5_init_creds_context ctx,
 			    struct krb5_fast_state *state,
-			    krb5_data *in,
+			    const krb5_data *in,
 			    krb5_data *out,
 			    krb5_realm *out_realm,
 			    unsigned int *flags)
diff --git a/lib/krb5/init_creds_pw.c b/lib/krb5/init_creds_pw.c
index 25767e31f..b3266a1f4 100644
--- a/lib/krb5/init_creds_pw.c
+++ b/lib/krb5/init_creds_pw.c
@@ -2964,7 +2964,7 @@ available_padata_count(METHOD_DATA *md)
 static krb5_error_code
 init_creds_step(krb5_context context,
 		krb5_init_creds_context ctx,
-		krb5_data *in,
+		const krb5_data *in,
 		krb5_data *out,
 		krb5_realm *out_realm,
 		unsigned int *flags)
@@ -3460,7 +3460,7 @@ init_creds_step(krb5_context context,
 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 krb5_init_creds_step(krb5_context context,
 		     krb5_init_creds_context ctx,
-		     krb5_data *in,
+		     const krb5_data *in,
 		     krb5_data *out,
 		     krb5_realm *out_realm,
 		     unsigned int *flags)