CVE-2021-31196Microsoft Exchange Server Remote Code Execution Vulnerability
- 7.2HighCVSS base score
- 54.1%Exploitation in 30 daysEPSS · top 1.0% of all CVEs
- YesKnown exploitedin CISA's KEV since 21 Aug 2024
- YesPublic exploitsa reference or SSVC says so
Description
Microsoft Exchange Server Remote Code Execution Vulnerability
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Microsoft Exchange Server Information Disclosure Vulnerability.
- Added
- 21 Aug 2024
- Fix due (US federal)
- 11 Sept 2024
- Used by ransomware
- Not known
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 21 Aug 2024.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By microsoft
- 3 months later
· 3 months later
Published
- 3 years later
· 3 years later
Added to CISA KEV
Known exploited in the wild
- 24 months later
· 24 months 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 | High7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C |
| NVDNVD · Analyzed | 3.1 | High7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 54.1% · top 1.0% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.2.
Affected products
Microsoft · Microsoft Exchange Server 2013 Cumulative Update 23
- affected 15.00.0 – < 15.00.1497.023
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 20
- affected 15.01.0 – < 15.01.2242.012
Microsoft · Microsoft Exchange Server 2016 Cumulative Update 21
- affected 15.01.0 – < 15.01.2308.014
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 10
- affected 15.02.0 – < 15.02.0922.013
Microsoft · Microsoft Exchange Server 2019 Cumulative Update 9
- affected 15.02.0 – < 15.02.0858.015
References
References3
- Microsoft Exchange Server Remote Code Execution Vulnerability (opens in a new tab)vendor-advisorypatch
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31196 (opens in a new tab)x_refsource_MISCx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31196 (opens in a new tab)government-resource
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)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-18109 (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-2021-31196)Record last updated .