CVE-2021-30500

HIGHNVD 7.87.8—

7.8

Null pointer dereference was found in upx PackLinuxElf::canUnpack() in p_lx_elf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

CVSS v3: 7.8
EG Score: 7.8(medium)
EPSS: 61.6%
KEV: Not listed

Published

May 27, 2021

Last Modified

April 11, 2025

References (6)

secalert@redhathttps://bugzilla.redhat.com/show_bug.cgi?id=1948692
secalert@redhathttps://github.com/upx/upx/commit/90279abdfcd235172eab99651043051188938dcc
secalert@redhathttps://github.com/upx/upx/issues/485
af854a3a-2127-422b-91ae-364da2661108https://bugzilla.redhat.com/show_bug.cgi?id=1948692
af854a3a-2127-422b-91ae-364da2661108https://github.com/upx/upx/commit/90279abdfcd235172eab99651043051188938dcc
af854a3a-2127-422b-91ae-364da2661108https://github.com/upx/upx/issues/485

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-476NULL Pointer Dereference

Data Freshness Timeline

(refreshed 11× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-04 13:10 UTCepss_batch
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2026-05-26 16:01 UTCEG score recompute
2026-05-26 16:01 UTCGHSA enrichment
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Frequently asked(5)

What is CVE-2021-30500?

CVE-2021-30500 is a high vulnerability published on May 27, 2021. Null pointer dereference was found in upx PackLinuxElf::canUnpack() in plxelf.cpp,in version UPX 4.0.0. That allow attackers to execute arbitrary code and cause a denial of service via a crafted file.

When was CVE-2021-30500 disclosed?

CVE-2021-30500 was first published in the National Vulnerability Database on May 27, 2021, 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-2021-30500 actively exploited?

CVE-2021-30500 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 61.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-30500?

CVE-2021-30500 has a CVSS v3 base score of 7.8 (NVD).

How do I remediate CVE-2021-30500?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-30500, 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.

Dependency Blast Radius

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CVE-2021-30500

📅 Published

🔄 Last Modified

🔗 References (6)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-30500?

🔗 Related CVEs(same CWE)

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Published

Last Modified

References (6)

Frequently asked(5)

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