What is CVE-2019-20021?

CVE-2019-20021 is a medium vulnerability published on December 27, 2019. A heap-based buffer over-read was discovered in canUnpack in p_mach.cpp in UPX 3.95 via a crafted Mach-O file.

When was CVE-2019-20021 disclosed?

CVE-2019-20021 was first published in the National Vulnerability Database on December 27, 2019, with the most recent update on April 11, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2019-20021 actively exploited?

CVE-2019-20021 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 55.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2019-20021?

CVE-2019-20021 has a CVSS v3 base score of 5.5 (NVD).

How do I remediate CVE-2019-20021?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2019-20021, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

CVE-2019-20021

MEDIUMNVD 5.55.5—

5.5

A heap-based buffer over-read was discovered in canUnpack in p_mach.cpp in UPX 3.95 via a crafted Mach-O file.

CVSS v3: 5.5
EG Score: 5.5(medium)
EPSS: 55.7%
KEV: Not listed

References (10)

cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2020-02/msg00003.html
cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2020-02/msg00007.html
cve@mitrehttps://github.com/upx/upx/issues/315
cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D7XU42G6MUQQXHWRP7DCF2JSIBOJ5GOO/
cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EUTVSTXAFTD552NO2K2RIF6MDQEHP3BE/
af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00003.html
af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00007.html
af854a3a-2127-422b-91ae-364da2661108https://github.com/upx/upx/issues/315
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D7XU42G6MUQQXHWRP7DCF2JSIBOJ5GOO/
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EUTVSTXAFTD552NO2K2RIF6MDQEHP3BE/

Is Your Infrastructure Affected by CVE-2019-20021?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs

CVE-2019-20021

Published

Last Modified

References (10)

Weakness Classification(1)

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2019-20021?

Same CWE

CVE-2019-20021

📅 Published

🔄 Last Modified

🔗 References (10)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2019-20021?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (10)

Frequently asked(5)

Related CVEs(same CWE)