Vulnerability in Google Tensorflow
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<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.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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 2.5 (Low). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.002 (7.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 7.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Google Tensorflow
- Tensorflow — versions < 2.1.4, >= 2.2.0, < 2.2.3, >= 2.3.0, < 2.3.3
Weakness classification (CWE)
References
- github.com/tensorflow/tensorflow/security/advisories/GHSA-3qxp-qjq7-w4hf (Exploit, Patch, Third Party Advisory)
- github.com/tensorflow/tensorflow/commit/26eb323554ffccd173e8a79a8c05c15b685ae4d1 (Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-29531?
- CVE-2021-29531 is a low-severity vulnerability in Google Tensorflow, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 2.5/10. Published 2021-05-14.
- How severe is CVE-2021-29531?
- Low severity. CVSS v3 base score is 2.5 out of 10.