CVE-2021-37679

Advisory

Tensorflow-gpu version 2.3.4, 2.4.3, 2.5.1 and 2.6.0 include a fix for CVE-2021-37679:
In affected versions it is possible to nest a "tf.map_fn" within another "tf.map_fn" call. However, if the input tensor is a "RaggedTensor" and there is no function signature provided, code assumes the output is a fully specified tensor and fills output buffer with uninitialized contents from the heap. The "t" and "z" outputs should be identical, however this is not the case. The last row of "t" contains data from the heap which can be used to leak other memory information. The bug lies in the conversion from a "Variant" tensor to a "RaggedTensor". The implementation (https://github.com/tensorflow/tensorflow/blob/460e000de3a83278fb00b61a16d161b1964f15f4/tensorflow/core/kernels/ragged_tensor_from_variant_op.cc#L177-L190) does not check that all inner shapes match and this results in the additional dimensions. The same implementation can result in data loss, if input tensor is tweaked. The Tensorflow team has patched the issue in GitHub commit 4e2565483d0ffcadc719bd44893fb7f609bb5f12.
https://github.com/tensorflow/tensorflow/security/advisories/GHSA-g8wg-cjwc-xhhp
https://github.com/tensorflow/tensorflow/commit/4e2565483d0ffcadc719bd44893fb7f609bb5f12

Affected package

Affected versions

Fixed versions

Vulnerability changelog

This vulnerability has no description

Resources

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-37679
• https://github.com/tensorflow/tensorflow/commit/4e2565483d0ffcadc719bd44893fb7f609bb5f12
• https://github.com/tensorflow/tensorflow/security/advisories/GHSA-g8wg-cjwc-xhhp