diff --git a/lib/gssapi/krb5/acquire_cred.c b/lib/gssapi/krb5/acquire_cred.c
index 95b99e149..295172442 100644
--- a/lib/gssapi/krb5/acquire_cred.c
+++ b/lib/gssapi/krb5/acquire_cred.c
@@ -105,7 +105,7 @@ static OM_uint32 acquire_initiator_cred
 		  (OM_uint32 * minor_status,
 		   krb5_context context,
 		   gss_const_OID credential_type,
-		   void *credential_data,
+		   const void *credential_data,
 		   const gss_name_t desired_name,
 		   OM_uint32 time_req,
 		   gss_const_OID desired_mech,
@@ -368,7 +368,7 @@ OM_uint32 GSSAPI_CALLCONV _gsskrb5_acquire_cred_ext
 (OM_uint32 * minor_status,
  const gss_name_t desired_name,
  gss_const_OID credential_type,
- void *credential_data,
+ const void *credential_data,
  OM_uint32 time_req,
  gss_const_OID desired_mech,
  gss_cred_usage_t cred_usage,