How severe is CVE-2020-15523?

CVE-2020-15523 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-15523 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-15523?

CVE-2020-15523 primarily affects Python. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-15523?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-15523 published?

CVE-2020-15523 was published on 2020-07-04 and last updated on 2026-06-17.

CVE-2020-15523

CVE-2020-15523 is a high-severity vulnerability in Python with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-427.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.9
EPSS exploit prediction: 1% (55th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-427
Affected product: Python
Published: 2020-07-04
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2020-15523?: 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.
How severe is CVE-2020-15523?: CVE-2020-15523 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-15523 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-15523?: CVE-2020-15523 primarily affects Python. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-15523?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-15523 published?: CVE-2020-15523 was published on 2020-07-04 and last updated on 2026-06-17.

References

Affected products (13)

cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.8.4:rc1:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:alpha1:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:alpha2:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:alpha3:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:alpha4:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:alpha5:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:alpha6:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:beta1:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:beta2:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:beta3:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:beta4:*:*:*:*:*:*
cpe:2.3:a:netapp:snapcenter:-:*:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

120.28.109.188 (ipv4-addr)
120.224.15.67 (ipv4-addr)
141.109.168.51 (ipv4-addr)
222.88.237.152 (ipv4-addr)