CVE-2021-29531 Information

Jun 07, 2022 cve

Description

TensorFlow is an end-to-end open source platform for machine learning. An attacker can trigger a CHECK fail in PNG encoding by providing an empty input tensor as the pixel data. This is because the implementation(https://github.com/tensorflow/tensorflow/blob/e312e0791ce486a80c9d23110841525c6f7c3289/tensorflow/core/kernels/image/encode_png_op.ccL57-L60) only validates that the total number of pixels in the image does not overflow. Thus an attacker can send an empty matrix for encoding. However if the tensor is empty then the associated buffer is nullptr. Hence when calling png::WriteImageToBuffer(https://github.com/tensorflow/tensorflow/blob/e312e0791ce486a80c9d23110841525c6f7c3289/tensorflow/core/kernels/image/encode_png_op.ccL79-L93) the first argument (i.e. image.flat<T>().data()) is NULL. This then triggers the CHECK_NOTNULL in the first line of png::WriteImageToBuffer(https://github.com/tensorflow/tensorflow/blob/e312e0791ce486a80c9d23110841525c6f7c3289/tensorflow/core/lib/png/png_io.ccL345-L349). Since image is null this results in abort being called after printing the stacktrace. Effectively this allows an attacker to mount a denial of service attack. The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2 TensorFlow 2.3.3 TensorFlow 2.2.3 and TensorFlow 2.1.4 as these are also affected and still in supported range.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

LOW

LOW

LOW

NONE

UNCHANGED

NONE

NONE

HIGH

5.5

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