In Python 3.6 through 3.6.10, 3.7 through 3.7.8, 3.8 through 3.8.4rc1, and 3.9 through 3.9.0b4 on Windows, a Trojan horse python3.dll might be used in cases where CPython is embedded in a native application. This occurs because python3X.dll may use an invalid search path for python3.dll loading (after Py_SetPath has been used). NOTE: this issue CANNOT occur when using python.exe from a standard (non-embedded) Python installation on Windows.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-15523
• python/cpython#21297
• https://bugs.python.org/issue29778
• https://security.netapp.com/advisory/ntap-20210312-0004/