CVE-2021-28481Microsoft Exchange Server Remote Code Execution Vulnerability
- 9.8CriticalCVSS base score
- 36.2%Exploitation in 30 daysEPSS · top 1.5% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- 1Public exploitsMetasploit, Nuclei and Exploit-DB
Description
Microsoft Exchange Server Remote Code Execution Vulnerability
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. The public collections list a Nuclei template for it.
Show the exploits1
Nuclei templates1 template
- Microsoft Exchange - Pre-Auth SSRF / ACL Bypass (ProxyNotFound) (Nuclei template) (opens in a new tab)
http/cves/2021/CVE-2021-28481.yamlSeverity critical
Modules, templates and exploits as listed by the Metasploit Framework (BSD-3-Clause), ProjectDiscovery's Nuclei templates (MIT) and the Exploit Database (GPLv2), read once a day. Where the data comes from
Timeline
ID reserved
By microsoft
- 29 days later
· 29 days later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoftCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C |
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 36.2% · top 1.5% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 9
- affected 15.02.0 – < 15.02.0858.010
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 20
- affected 15.01.0 – < 15.01.2242.008
Microsoft · Microsoft Exchange Server 2013 Cumulative Update 23
- affected 15.00.0 – < 15.00.1497.015
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 19
- affected 15.01.0 – < 15.01.2176.012
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 8
- affected 15.02.0 – < 15.02.0792.013
References
References1
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28481 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-15159 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-28481)Record last updated .