CVE-2021-29531

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.cc#L57-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.cc#L79-L93), the first argument (i.e., `image.flat().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.cc#L345-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.

Link	Resource
https://github.com/tensorflow/tensorflow/commit/26eb323554ffccd173e8a79a8c05c15b685ae4d1	Patch Third Party Advisory
https://github.com/tensorflow/tensorflow/security/advisories/GHSA-3qxp-qjq7-w4hf	Exploit Patch

Configuration 1

cpe:2.3:a:google:tensorflow:*:*:*:*:*:*:*:* cpe:2.3:a:google:tensorflow:*:*:*:*:*:*:*:* cpe:2.3:a:google:tensorflow:*:*:*:*:*:*:*:* cpe:2.3:a:google:tensorflow:*:*:*:*:*:*:*:*

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Published : 2021-05-14 08:15

Updated : 2021-05-20 03:46

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NVD link : CVE-2021-29531

Mitre link : CVE-2021-29531

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CWE-754