CVE-2021-28465

HIGHPre-NVD 7.87.8—

7.8

Web Media Extensions Remote Code Execution Vulnerability

CVSS v3: 7.8
EG Score: 7.8(medium)
EPSS: 94.5%
KEV: Not listed

Published

May 11, 2021

Last Modified

May 28, 2026

Advisory Details (3)

Auto-updated May 28, 2026

Patch available. Sources: microsoft.

generic

ZDI-21-579 | Zero Day Initiative

https://www.zerodayinitiative.com/advisories/ZDI-21-579/

generic

ZDI-21-572 | Zero Day Initiative

https://www.zerodayinitiative.com/advisories/ZDI-21-572/

microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28465

Weakness Classification(2)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Microsoft MSRCCVE-2021-284652021-05-11
Web Media Extensions Remote Code Execution Vulnerability

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
2026-06-04 13:10 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 16:46 UTCEG score recompute
2026-05-26 16:46 UTCVendor advisory
2026-05-26 16:46 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-28465?

CVE-2021-28465 is a high vulnerability published on May 11, 2021. Web Media Extensions Remote Code Execution Vulnerability

When was CVE-2021-28465 disclosed?

CVE-2021-28465 was first published in the National Vulnerability Database on May 11, 2021, with the most recent update on May 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-28465 actively exploited?

CVE-2021-28465 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 94.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-28465?

CVE-2021-28465 has a CVSS v3 base score of 7.8 (NVD).

How do I remediate CVE-2021-28465?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-28465, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-28465

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Is Your Infrastructure Affected by CVE-2021-28465?

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CVE-2021-28465

Published

Last Modified

Advisory Details (3)

ZDI-21-579 | Zero Day Initiative

ZDI-21-572 | Zero Day Initiative

Security Update Guide - Microsoft Security Response Center

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-28465?

Same vendor

Same CWE

CVE-2021-28465

📅 Published

🔄 Last Modified

📋 Advisory Details (3)

ZDI-21-579 | Zero Day Initiative

ZDI-21-572 | Zero Day Initiative

Security Update Guide - Microsoft Security Response Center

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-28465?

🔗 Related CVEs(same vendor + same CWE)

Same vendor

Same CWE

Published

Last Modified

Advisory Details (3)

Frequently asked(5)

Related CVEs(same vendor + same CWE)