CVE-2021-29521

critical
Published 2021-05-21 · Modified 2023-12-06
CVSS v3
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
CVSS v2
VIR risk
9.5

Description

TensorFlow is an end-to-end open source platform for machine learning. Specifying a negative dense shape in `tf.raw_ops.SparseCountSparseOutput` results in a segmentation fault being thrown out from the standard library as `std::vector` invariants are broken. This is because the implementation(https://github.com/tensorflow/tensorflow/blob/8f7b60ee8c0206a2c99802e3a4d1bb55d2bc0624/tensorflow/core/kernels/count_ops.cc#L199-L213) assumes the first element of the dense shape is always positive and uses it to initialize a `BatchedMap<T>` (i.e., `std::vector<absl::flat_hash_map<int64,T>>`(https://github.com/tensorflow/tensorflow/blob/8f7b60ee8c0206a2c99802e3a4d1bb55d2bc0624/tensorflow/core/kernels/count_ops.cc#L27)) data structure. If the `shape` tensor has more than one element, `num_batches` is the first value in `shape`. Ensuring that the `dense_shape` argument is a valid tensor shape (that is, all elements are non-negative) solves this issue. The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2 and TensorFlow 2.3.3.

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-29521

OS impact

OSVersionStatusFixed in
arch archfixed2.5.0-1
debian debianforkyfixed0
debian debiansidfixed0

Package impact

EcosystemPackageVulnerableFixed
python PyPItensorflow>=2.3.0,<2.3.32.3.3
python PyPItensorflow>=2.4.0,<2.4.22.4.2
python PyPItensorflow-cpu>=2.3.0,<2.3.32.3.3
python PyPItensorflow-cpu>=2.4.0,<2.4.22.4.2
python PyPItensorflow-gpu>=2.3.0,<2.3.32.3.3
python PyPItensorflow-gpu>=2.4.0,<2.4.22.4.2
python PyPItensorflow-cpu<c57c0b9f3a4f8684f3489dd9a9ec627ad8b599f5||>=2.4.0,<2.4.2c57c0b9f3a4f8684f3489dd9a9ec627ad8b599f5
python PyPItensorflow-gpu<c57c0b9f3a4f8684f3489dd9a9ec627ad8b599f5||>=2.4.0,<2.4.2c57c0b9f3a4f8684f3489dd9a9ec627ad8b599f5
python PyPItensorflow<c57c0b9f3a4f8684f3489dd9a9ec627ad8b599f5||>=2.4.0,<2.4.2c57c0b9f3a4f8684f3489dd9a9ec627ad8b599f5

References

Verify integrity in audit chain (admin only). AS-IS.