{"id":"CVE-2021-29521","aliases":["BIT-tensorflow-2021-29521","GHSA-hr84-fqvp-48mm","PYSEC-2021-158","PYSEC-2021-449","PYSEC-2021-647"],"url":"https://o3.security/vulnerability/CVE-2021-29521","summary":"Segfault in SparseCountSparseOutput","details":"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.","published":"2021-05-14T20:15:11.567Z","modified":"2026-08-07T17:31:56.333974Z","cvss":{"score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"tensorflow","fixedVersion":"2.3.3"},{"ecosystem":"PyPI","name":"tensorflow","fixedVersion":"2.4.2"},{"ecosystem":"PyPI","name":"tensorflow-cpu","fixedVersion":"2.3.3"},{"ecosystem":"PyPI","name":"tensorflow-cpu","fixedVersion":"2.4.2"},{"ecosystem":"PyPI","name":"tensorflow-gpu","fixedVersion":"2.3.3"},{"ecosystem":"PyPI","name":"tensorflow-gpu","fixedVersion":"2.4.2"}],"fix":{"url":"https://github.com/tensorflow/tensorflow/commit/c57c0b9f3a4f8684f3489dd9a9ec627ad8b599f5","label":"tensorflow/tensorflow@c57c0b9"},"references":[{"type":"FIX","url":"https://github.com/tensorflow/tensorflow/commit/c57c0b9f3a4f8684f3489dd9a9ec627ad8b599f5"},{"type":"FIX","url":"https://github.com/tensorflow/tensorflow/security/advisories/GHSA-hr84-fqvp-48mm"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T17:31:56.333974Z"}}