Hi, 

We can't tell for sure what this symptom may be. We can see what looks like a borer hole in the bark in the second photo. It could be sap oozing from the trunk, especially this time of year as the sap starts to run in maple trees. A wood boring insect or another bark wound could cause the sap to leak. It could also be a sign of slime flux. There isn't a 'cure' for slime flux and if the tree isn't in major decline you can just monitor for symptoms. This is the same for any borers in the tree. There wouldn't be a cure if there were borers in the wood at this point either. Typically bark beetles start to infest trees as a secondary response to an underlying stress issue whether it be a disease, wound, or root problem. 

You should consult with a certified arborist though for any care recommendations and overall tree health. Search for one in your area at https://www.treesaregood.org/ 

Let us know if you have further questions or would like us to weigh in on an arborists recommendations. 

Emily