CVE-2019-20477

highpriority · track · 41EPSS 0.051 · 92 %ileEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

5.11% (92nd) EPSS

CVSS 7.5 · high

Is it mine?

6 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-27

PyYAML 5.1 through 5.1.2 has insufficient restrictions on the load and load_all functions because of a class deserialization issue, e.g., Popen is a class in the subprocess module. NOTE: this issue exists because of an incomplete fix for CVE-2017-18342.

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.5–9.8

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · OSV

v3.19criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-502USprimaryCWE-502US

affected products (6)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
fedoraproject fedora= 30nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
fedoraproject fedora= 31nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
pyyaml pyyaml5.1 → 5.1.2nvdUScpe:2.3:a:pyyaml:pyyaml:*:*:*:*:*:*:*:*
PyPI pyyaml5.1 → 5.2osvUSpkg:pypi/pyyaml
PyPI pyyaml5.1 → 5.2b1osvUSpkg:pypi/pyyaml

advisories (2)

Vendor and ecosystem advisories describing this.

GHSA-3pqx-4fqf-j49fDeserialization of Untrusted Data in PyYAML2021-04-20ghsa · osvUS
PyYAML 5.1 through 5.1.2 has insufficient restrictions on the load and load_all functions because of a class deserialization issue, e.g., Popen is a class in the subprocess module. NOTE: this issue exists because of an incomplete fix for CVE-2017-18342.
PYSEC-2020-1762020-02-19vendor · osvUS
PyYAML 5.1 through 5.1.2 has insufficient restrictions on the load and load_all functions because of a class deserialization issue, e.g., Popen is a class in the subprocess module. NOTE: this issue exists because of an incomplete fix for CVE-2017-18342.

also known as (6)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv nvd NVD CVE.org MITRE

published 2020-02-19modified 2026-06-17

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+3739 more

references (15)

External citations — patches, advisories, analysis.

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