CVE-2021-43255

MEDIUMNVD 5.55.5—

5.5

Microsoft Office Trust Center Spoofing Vulnerability

CVSS v3: 5.5
EG Score: 5.5(medium)
EPSS: 82.9%
KEV: Not listed

Published

December 15, 2021

Last Modified

May 19, 2026

References (2)

secure@microsofthttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43255
af854a3a-2127-422b-91ae-364da2661108https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43255

Vendor Advisories for CVE-2021-43255(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

GHSA-x5f4-jxc9-j6mv
GitHub Security AdvisoriesMedium
Microsoft Office Trust Center Spoofing Vulnerability

Frequently asked(5)

What is CVE-2021-43255?

CVE-2021-43255 is a medium vulnerability published on December 15, 2021. Microsoft Office Trust Center Spoofing Vulnerability

When was CVE-2021-43255 disclosed?

CVE-2021-43255 was first published in the National Vulnerability Database on December 15, 2021, with the most recent update on May 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-43255 actively exploited?

CVE-2021-43255 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 82.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-43255?

CVE-2021-43255 has a CVSS v3 base score of 5.5 (NVD).

How do I remediate CVE-2021-43255?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-43255, 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-2021-43255

📅 Published

🔄 Last Modified

🔗 References (2)

📣 Vendor Advisories for CVE-2021-43255(1)

❓ Frequently asked(5)