CVE-2021-37663

7.8 HIGH

📋 TL;DR

This vulnerability in TensorFlow's QuantizeV2 operation allows attackers to trigger undefined behavior by accessing invalid memory locations. Attackers can cause crashes or potentially execute arbitrary code by exploiting incomplete validation of input parameters. All TensorFlow users running affected versions are at risk.

💻 Affected Systems

Products:
  • TensorFlow
Versions: TensorFlow 2.3.0 to 2.5.0, and earlier versions if using QuantizeV2
Operating Systems: All platforms running TensorFlow
Default Config Vulnerable: ⚠️ Yes
Notes: Vulnerability exists in default TensorFlow installations when QuantizeV2 operation is used with malformed inputs.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, data theft, or service disruption.

🟠

Likely Case

Application crashes, denial of service, or memory corruption leading to unstable behavior.

🟢

If Mitigated

No impact if patched or if vulnerable code paths are not invoked.

🌐 Internet-Facing: MEDIUM - Requires specific API calls to vulnerable function, but common in ML inference services.
🏢 Internal Only: MEDIUM - Similar risk profile, but attack surface limited to internal users/applications.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ✅ No
Complexity: MEDIUM

Exploitation requires ability to call QuantizeV2 with controlled parameters, typically through ML model inference APIs.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: TensorFlow 2.6.0, 2.5.1, 2.4.3, 2.3.4

Vendor Advisory: https://github.com/tensorflow/tensorflow/security/advisories/GHSA-g25h-jr74-qp5j

Restart Required: No

Instructions:

1. Update TensorFlow to patched version using pip: 'pip install --upgrade tensorflow==2.6.0' 2. Verify installation with 'python -c "import tensorflow as tf; print(tf.__version__)"' 3. Test QuantizeV2 operations to ensure stability.

🔧 Temporary Workarounds

Input Validation Wrapper

all

Add validation layer before calling QuantizeV2 to ensure min_range and max_range have same non-zero length

# Python code to wrap QuantizeV2 calls
import tensorflow as tf

def safe_quantize_v2(input_tensor, min_range, max_range, axis=-1):
    if axis != -1:
        if not (min_range.shape == max_range.shape):
            raise ValueError("min_range and max_range must have same shape")
        if min_range.shape[0] != input_tensor.shape[axis]:
            raise ValueError("Range dimensions must match axis dimension")
    return tf.raw_ops.QuantizeV2(input=input_tensor, min_range=min_range, max_range=max_range, axis=axis)

🧯 If You Can't Patch

  • Disable or restrict access to APIs that call QuantizeV2 operation
  • Implement network segmentation to isolate TensorFlow services from critical systems

🔍 How to Verify

Check if Vulnerable:

Check TensorFlow version: 'python -c "import tensorflow as tf; print(tf.__version__)"' - versions 2.3.0-2.5.0 are vulnerable.

Check Version:

python -c "import tensorflow as tf; print('TensorFlow version:', tf.__version__)"

Verify Fix Applied:

After patching, test QuantizeV2 with malformed inputs to ensure proper error handling instead of crashes.

📡 Detection & Monitoring

Log Indicators:

  • Segmentation faults in TensorFlow processes
  • Memory access violation errors
  • Unexpected TensorFlow service restarts

Network Indicators:

  • Unusual spikes in ML inference API errors
  • Increased failed quantization requests

SIEM Query:

source="tensorflow" AND ("segmentation fault" OR "memory violation" OR "QuantizeV2 error")

🔗 References

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