CVE-2021-41208 : Security Advisory and Response

TensorFlow is an open source machine learning platform with a vulnerability in its boosted trees code that may lead to denial of service attacks and other security risks.

Understanding CVE-2021-41208

Incomplete validation in the boosted trees code of TensorFlow can result in critical security implications and impact system availability, confidentiality, and integrity.

What is CVE-2021-41208?

TensorFlow's boosted trees code lacks proper validation, enabling attackers to execute denial of service attacks, trigger

nullptr

dereferences, and abuse undefined behavior, leading to heap buffer overflows.

The Impact of CVE-2021-41208

Severity: High (Base Score: 8.8)
CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attackers can exploit this vulnerability locally with low privileges, causing a significant availability impact and compromising confidentiality and integrity.

Technical Details of CVE-2021-41208

The vulnerability lies in the incomplete validation of boosted trees code within TensorFlow.

Vulnerability Description

The issue allows attackers to trigger denial of service by dereferencing

nullptr

s or

CHECK

-failures.
Attackers can abuse undefined behavior by binding references to

nullptr

s, potentially leading to heap buffer overflows.

Affected Systems and Versions

The following versions of TensorFlow are affected:

TensorFlow >= 2.6.0 and < 2.6.1
TensorFlow >= 2.5.0 and < 2.5.2
TensorFlow < 2.4.4

Exploitation Mechanism

Attackers can perform various attacks, such as triggering denial of service, abusing undefined behavior, and reading/writing from heap buffers.

Mitigation and Prevention

It is crucial to take immediate steps to mitigate this vulnerability and implement long-term security practices.

Immediate Steps to Take

Upgrade TensorFlow to version 2.7.0 or apply patches from 2.6.1, 2.5.2, and 2.4.4.
Consider avoiding the use of TensorFlow's boosted trees APIs.

Long-Term Security Practices

Regularly update TensorFlow to the latest versions to address security issues promptly.

Patching and Updates

The fix for CVE-2021-41208 will be included in TensorFlow 2.7.0, with patches available for versions 2.6.1, 2.5.2, and 2.4.4.