CVE-2021-31196
Confirmed PUBLISHEDMicrosoft Exchange Server Remote Code Execution Vulnerability
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
Microsoft Exchange Server Remote Code Execution Vulnerability
- CVE Published
- Jul 14, 2021
- Exploitation Reported
- Aug 21, 2024
- CVSS
- 7.2 High
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Microsoft |
Microsoft Exchange Server 2019 Cumulative Update 9
|
15.02.0 to < 15.02.0858.015 |
Affected |
| Microsoft |
Microsoft Exchange Server 2016 Cumulative Update 20
|
15.01.0 to < 15.01.2242.012 |
Affected |
| Microsoft |
Microsoft Exchange Server 2013 Cumulative Update 23
|
15.00.0 to < 15.00.1497.023 |
Affected |
| Microsoft |
Microsoft Exchange Server 2016 Cumulative Update 21
|
15.01.0 to < 15.01.2308.014 |
Affected |
| Microsoft |
Microsoft Exchange Server 2019 Cumulative Update 10
|
15.02.0 to < 15.02.0922.013 |
Affected |
CVE References
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31196 portal.msrc.microsoft.com · CVE Record https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CV...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2024-08-21 00:00 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
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
Exploitation Status
Exploited in the wild
Recorded 2024-08-21 00:00:00 UTC · CISA
Scanner Integrations
| Scanner | Reference | Detected |
|---|---|---|
| Nessus | https://www.tenable.com/plugins/nessus/151664 | Jun 02, 2025 |
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
09:26 UTC about 1 year ago09:26 UTC · about 1 year ago
Nessus plugin available
Scanner coverage available
-
00:00 UTC almost 2 years ago00:00 UTC · almost 2 years ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
17:53 UTC about 5 years ago17:53 UTC · about 5 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC over 5 years ago00:00 UTC · over 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-31196
{
"cve_id": "CVE-2021-31196",
"title": "Microsoft Exchange Server Remote Code Execution Vulnerability",
"affected_vendor": "Microsoft",
"affected_product": "Microsoft Exchange Server 2019 Cumulative Update 9, Microsoft Exchange Server 2016 Cumulative Update 20, Microsoft Exchange Server 2013 Cumulative Update 23, Microsoft Exchange Server 2016 Cumulative Update 21, Microsoft Exchange Server 2019 Cumulative Update 10",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 7.2,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}