CVE-2021-41204: 
Python vulnerability analysis and mitigation

TensorFlow, an open source platform for machine learning, was affected by a vulnerability (CVE-2021-41204) during its Grappler optimizer phase. The issue was discovered where constant folding might attempt to deep copy a resource tensor, resulting in a segmentation fault since these tensors are not supposed to change. The vulnerability was disclosed on November 4, 2021, affecting TensorFlow versions prior to 2.7.0 (GitHub Advisory).

The vulnerability occurs in TensorFlow's Grappler optimizer phase when attempting to perform constant folding operations on resource tensors. The core issue lies in the improper handling of resource tensors during deep copy operations, which violates the fundamental assumption that these tensors should remain unchanged. The vulnerability has been assigned a CVSS v3.1 Base Score of 5.5 MEDIUM (Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) (NVD).

When exploited, this vulnerability results in a segmentation fault, which can lead to application crashes. This could potentially cause denial of service conditions in systems running affected versions of TensorFlow (GitHub Advisory).

The vulnerability was patched in TensorFlow version 2.7.0. The fix was also backported to versions 2.6.1, 2.5.2, and 2.4.4. The patch prevents constant folding of resource tensors by adding a check in the IsConstantFoldable function. Users are advised to upgrade to these patched versions (GitHub Advisory).