CVE-2021-34473
At a glance
- Severity
- CRITICAL 9.1
- Exploitation
- Known exploited (CISA KEV) · added 2021-11-03
Exploited per ENISA since 2021-11-03 - EPSS
- EPSS 100.00 % · percentile 100 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- microsoft
- NVD status
- Analyzed
Description
Microsoft Exchange Server Remote Code Execution Vulnerability
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | CRITICAL 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C | microsoft |
| CVSS 3.1 | CRITICAL 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N | NVD · secure@microsoft.com (Secondary) |
| CVSS 3.1 | CRITICAL 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | NVD · nvd@nist.gov (Secondary) |
| CVSS 2.0 | HIGH 10.0 | AV:N/AC:L/Au:N/C:C/I:C/A:C | NVD · nvd@nist.gov (Primary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2021-21128
- GCVE · GCVE-0-2021-34473
CERT-FR advisories
- CERTFR-2021-AVI-522 — Multiples vulnérabilités dans les produits Microsoft · cert.ssi.gouv.fr
- CERTFR-2021-ALE-017 — Multiples vulnérabilités dans Microsoft Exchange · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
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:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| 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 2016 Cumulative Update 20 | affected 15.01.0 < 15.01.2242.008 |
| Microsoft · Microsoft Exchange Server 2019 Cumulative Update 8 | affected 15.02.0 < 15.02.0792.013 |
| Microsoft · Microsoft Exchange Server 2019 Cumulative Update 9 | affected 15.02.0 < 15.02.0858.010 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34473
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473
- https://www.zerodayinitiative.com/advisories/ZDI-21-821/
- http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| CISA Known Exploited Vulnerabilities | CC0 1.0 |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |