CVE-2021-28481Exchange Server Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability
Published Apr 14, 2021 · Updated Aug 3, 2024
Key Facts
Patch immediately- CVE-2021-28481 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Exchange Server (Microsoft).
- It is exploited in the wild, listed in Industry KEV feed since Jul 25, 2024. No public exploit code is known.
- EPSS estimates a 36% probability of exploitation in the next 30 days.
- Fixed versions are available, including Exchange Server 15.00.1497.015, Exchange Server 15.01.2176.012, Exchange Server 15.01.2242.008.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
36%
Higher than 98.4% of all scored CVEs
Exploit maturity
None known
ATLAS score
39/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Jul 25, 2024
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
None known
Public exploit code
0
Proof-of-concept links
In-the-wild evidence
5
Reports of active use
Advisories And Exploit References
- advisoryhttps://support.microsoft.com/en-us/topic/description-of-the-security-update-for-microsoft-exchange-server-2019-2016-and-2013-april-13-2021-kb5001779-8e08f3b3-fc7b-466c-bbb7-5d5aa16ef064
- advisoryUSOM advisory
- patchhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28481
Description
Microsoft Exchange Server Remote Code Execution Vulnerability
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Jul 25, 2024 | n/a | Not reported |
Affected Products
5 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Exchange ServerMicrosoft | 2013-cumulative_update_23, 2016-cumulative_update_19, 2016-cumulative_update_20, 2019-cumulative_update_8, 2019-cumulative_update_9 | 15.00.1497.015 |
Patched Releases
Exchange Server
15.00.1497.015, 15.01.2176.012, 15.01.2242.008, 15.02.0792.013, 15.02.0858.010
Timeline
Publicly disclosed
Apr 14, 2021
Added to Industry KEV feed
Jul 25, 2024
Last updated
Aug 3, 2024
References
- advisorysupport.microsoft.com · description-of-the-security-update-for-microsof…
- advisoryUSOM advisory
- patchportal.msrc.microsoft.com · CVE-2021-28481
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected: Exchange Server (Microsoft) versions 2013-cumulative_update_23, 2016-cumulative_update_19, 2016-cumulative_update_20, 2019-cumulative_update_8, 2019-cumulative_update_9. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Jul 25, 2024.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Exchange Server 15.00.1497.015, Exchange Server 15.01.2176.012, Exchange Server 15.01.2242.008.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2021-28481 On Your Attack Surface?
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