Vulnerability CVE-2021-29609

Vulnerability Name:

CVE-2021-29609 (CCN-201859)

Assigned:

2021-05-12

Published:

2021-05-12

Updated:

2021-05-20

Summary:

TensorFlow is an end-to-end open source platform for machine learning. Incomplete validation in `SparseAdd` results in allowing attackers to exploit undefined behavior (dereferencing null pointers) as well as write outside of bounds of heap allocated data. The implementation(https://github.com/tensorflow/tensorflow/blob/656e7673b14acd7835dc778867f84916c6d1cac2/tensorflow/core/kernels/sparse_add_op.cc) has a large set of validation for the two sparse tensor inputs (6 tensors in total), but does not validate that the tensors are not empty or that the second dimension of `*_indices` matches the size of corresponding `*_shape`. This allows attackers to send tensor triples that represent invalid sparse tensors to abuse code assumptions that are not protected by validation. 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 v3 Severity:

7.8 High (CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
6.8 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)

Exploitability Metrics:	Attack Vector (AV): Local Attack Complexity (AC): Low Privileges Required (PR): Low User Interaction (UI): None
Scope:	Scope (S): Unchanged
Impact Metrics:	Confidentiality (C): High Integrity (I): High Availibility (A): High

5.3 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H)
4.6 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H/E:U/RL:O/RC:C)

Exploitability Metrics:	Attack Vector (AV): Local Attack Complexity (AC): High Privileges Required (PR): Low User Interaction (UI): None
Scope:	Scope (S): Unchanged
Impact Metrics:	Confidentiality (C): None Integrity (I): Low Availibility (A): High

CVSS v2 Severity:

4.6 Medium (CVSS v2 Vector: AV:L/AC:L/Au:N/C:P/I:P/A:P)

Exploitability Metrics:	Access Vector (AV): Local Access Complexity (AC): Low Authentication (Au): None
Impact Metrics:	Confidentiality (C): Partial Integrity (I): Partial Availibility (A): Partial

4.5 Medium (CCN CVSS v2 Vector: AV:L/AC:H/Au:S/C:N/I:P/A:C)

Exploitability Metrics:	Access Vector (AV): Local Access Complexity (AC): High Athentication (Au): Single_Instance
Impact Metrics:	Confidentiality (C): None Integrity (I): Partial Availibility (A): Complete