CVE-2021-41225

A use of uninitialized value vulnerability in Tensorflow

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Attribution

This vulnerability has been reported by Qian Feng from Baidu Security Team.

TensorFlow's Grappler optimizer has a use of unitialized variable:

  const NodeDef* dequeue_node;
  for (const auto& train_node : train_nodes) {
    if (IsDequeueOp(*train_node)) {
      dequeue_node = train_node;
      break;
    }
  }

  if (dequeue_node) {
    ...
  }

If the train_nodes vector (obtained from the saved model that gets optimized) does not contain a Dequeue node, then dequeue_node is left unitialized.

CVE-2021-41225 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.6.1, 2.5.2, 2.4.4); upgrading removes the vulnerable code path.

Kodem intelligence

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We have patched the issue in GitHub commit 68867bf01239d9e1048f98cbad185bf4761bedd3.

The fix will be included in TensorFlow 2.7.0. We will also cherrypick this commit on TensorFlow 2.6.1, TensorFlow 2.5.2, and TensorFlow 2.4.4, as these are also affected and still in supported range.

1. What is CVE-2021-41225? CVE-2021-41225 is a medium-severity security vulnerability in tensorflow (pip), affecting versions >= 2.6.0, < 2.6.1. It is fixed in 2.6.1, 2.5.2, 2.4.4.
2. How severe is CVE-2021-41225? CVE-2021-41225 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2021-41225?
   • tensorflow (pip) (versions >= 2.6.0, < 2.6.1)
   • tensorflow-cpu (pip) (versions >= 2.6.0, < 2.6.1)
   • tensorflow-gpu (pip) (versions >= 2.6.0, < 2.6.1)
4. Is there a fix for CVE-2021-41225? Yes. CVE-2021-41225 is fixed in 2.6.1, 2.5.2, 2.4.4. Upgrade to this version or later.
5. Is CVE-2021-41225 exploitable, and should I be worried? Whether CVE-2021-41225 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2021-41225 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2021-41225?
   • Upgrade tensorflow to 2.6.1 or later
   • Upgrade tensorflow to 2.5.2 or later
   • Upgrade tensorflow to 2.4.4 or later
   • Upgrade tensorflow-cpu to 2.6.1 or later
   • Upgrade tensorflow-cpu to 2.5.2 or later
   • Upgrade tensorflow-cpu to 2.4.4 or later
   • Upgrade tensorflow-gpu to 2.6.1 or later
   • Upgrade tensorflow-gpu to 2.5.2 or later
   • Upgrade tensorflow-gpu to 2.4.4 or later

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