Is CVE-2019-20477 in the CISA KEV catalog?

No. CVE-2019-20477 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2019-20477?

CVE-2019-20477 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2019-20477?

CVE-2019-20477 has an EPSS score of 5.03% (91th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2019-20477?

Upgrade pyyaml on debian 11 to 5.2-1 or later.

CVE & CISA-KEV Catalog

CVE-2019-20477

CRITICALEPSS 91th pctl

9.8

CVSS v3

NVD

Description

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.

CWE-502Deserialization of Untrusted Data

How to fix

Remediation Available

pyyamlDebian

Fixed in:5.2-1CVE-2019-20477

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

5.03%probability of exploitation in 30 days

91stpercentile

High risk: more likely to be exploited than 91% of all known CVEs.

References

Exploit1

exploit-db.com

Third-Party Advisory1

github.com

Other references2

Related Vulnerabilities

Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-0669	High	7.2	100%	KEV + Ransom	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2021-35464	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2023-29300	Critical	9.8	100%	KEV + Ransom	-
CVE-2025-53770	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2022-47986	Critical	9.8	100%	KEV + Ransom	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.