CVE-2020-15523

Name: CVE-2020-15523
Creator: NVD / NIST
Published: 2020-07-04T23:15:10.313+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.90%

Last modified Jun 17, 2026

CVE-2020-15523 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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). EPSS estimates a 0.90% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Probability

0.90%

54.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Python	Python	>= 3.5.0, < 3.5.10	—
Python	Python	>= 3.6.0, < 3.6.12	—
Python	Python	>= 3.7.0, < 3.7.9	—
Python	Python	>= 3.8.0, < 3.8.4	—
Python	Python	3.8.4	Rc1
Python	Python	3.9.0	Alpha1
Netapp	Snapcenter	All versions	—

References

https://bugs.python.org/issue29778Issue Tracking, Patch, Vendor Advisory
https://github.com/python/cpython/pull/21297Patch, Third Party Advisory
https://security.netapp.com/advisory/ntap-20210312-0004/Issue Tracking, Patch, Third Party Advisory
https://bugs.python.org/issue29778Issue Tracking, Patch, Vendor Advisory
https://github.com/python/cpython/pull/21297Patch, Third Party Advisory
https://security.netapp.com/advisory/ntap-20210312-0004/Issue Tracking, Patch, Third Party Advisory

Timeline

Published: Jul 4, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-15523?

How severe is CVE-2020-15523?

CVE-2020-15523 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.90% probability of exploitation in the next 30 days.

How do I fix CVE-2020-15523?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-15523?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST