How severe is CVE-2021-28482?

CVE-2021-28482 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-28482 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 83% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28482?

CVE-2021-28482 primarily affects Microsoft Exchange Server. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-28482?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-28482 published?

CVE-2021-28482 was published on 2021-04-13 and last updated on 2026-06-17.

CVE-2021-28482

CVE-2021-28482 is a high-severity vulnerability in Microsoft Exchange Server with a CVSS 3.x base score of 8.8. Its EPSS exploit-prediction score of 83% places it in the 100th percentile, indicating an elevated likelihood of exploitation.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 9.0
EPSS exploit prediction: 83% (100th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Exchange Server
Published: 2021-04-13
Last modified: 2026-06-17

Description

Microsoft Exchange Server Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2021-28482?: Microsoft Exchange Server Remote Code Execution Vulnerability
How severe is CVE-2021-28482?: CVE-2021-28482 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-28482 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 83% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28482?: CVE-2021-28482 primarily affects Microsoft Exchange Server. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-28482?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-28482 published?: CVE-2021-28482 was published on 2021-04-13 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28482

Affected products (5)

cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:*

More vulnerabilities in Microsoft Exchange Server

CVE-2007-0213 — Critical (CVSS 10.0): Microsoft Exchange Server 2000 SP3, 2003 SP1 and SP2, and 2007 does not properly decode certain MIME encoded e-mails,…
CVE-2004-0840 — Critical (CVSS 10.0): The SMTP (Simple Mail Transfer Protocol) component of Microsoft Windows XP 64-bit Edition, Windows Server 2003, Windows…
CVE-2004-0574 — Critical (CVSS 10.0): The Network News Transfer Protocol (NNTP) component of Microsoft Windows NT Server 4.0, Windows 2000 Server, Windows…
CVE-1999-0385 — Critical (CVSS 10.0): The LDAP bind function in Exchange 5.5 has a buffer overflow that allows a remote attacker to conduct a denial of…
CVE-2024-21410 — Critical (CVSS 9.8): Microsoft Exchange Server Elevation of Privilege Vulnerability
CVE-2023-21709 — Critical (CVSS 9.8): Microsoft Exchange Server Elevation of Privilege Vulnerability

All CVEs affecting Microsoft Exchange Server →