Impact

The GraphDef format in TensorFlow does not allow self recursive functions. The runtime assumes that this invariant is satisfied. However, a GraphDef containing a fragment such as the following can be consumed when loading a SavedModel:

  library {
    function {
      signature {
        name: "SomeOp"
        description: "Self recursive op"
      }
      node_def {
        name: "1"
        op: "SomeOp"
      }
      node_def {
        name: "2"
        op: "SomeOp"
      }
    }
  } 

This would result in a stack overflow during execution as resolving each NodeDef means resolving the function itself and its nodes.

Patches

We have patched the issue in GitHub commit 448a16182065bd08a202d9057dd8ca541e67996c.

The fix will be included in TensorFlow 2.8.0. We will also cherrypick this commit on TensorFlow 2.7.1, TensorFlow 2.6.3, and TensorFlow 2.5.3, as these are also affected and still in supported range.

For more information

Please consult our security guide for more information regarding the security model and how to contact us with issues and questions.