CVE-2021-31201
Microsoft Enhanced Cryptographic Provider Elevation of Privilege Vulnerability
- CVSS
- 5.2Mediumscored by the publisher (CNA)
- Exploited in the wild
- Yes, in CISA KEV since 3 Nov 2021CISA deadline for US federal agencies: 17 Nov 2021
- EPSS
- 2.6%chance of exploitation in the next 30 daystop 15% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 8 Jun 2021analysed here 12 Nov 2026
Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)
Summary
Triage
- Exploitable
- At runtime
- Attack vector
- local
- Can a WAF block it?
- No. See why
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Microsoft Windows 10 Version 1507 | >= 10.0.0 and < 10.0.10240.18967Vendor says fixed in: not stated | |
| Microsoft Windows 10 Version 1607 | >= 10.0.0 and < 10.0.14393.4467Vendor says fixed in: not stated | |
| Microsoft Windows 10 Version 1809 | >= 10.0.0 and < 10.0.17763.1999Vendor says fixed in: not stated | |
| Microsoft Windows 10 Version 1909 | >= 10.0.0 and < 10.0.18363.1621Vendor says fixed in: not stated | |
| Microsoft Windows 10 Version 2004 | >= 10.0.0 and < 10.0.19041.1052Vendor says fixed in: not stated | |
| Microsoft Windows 10 Version 20H2 | >= 10.0.0 and < 10.0.19042.1052Vendor says fixed in: not stated | |
| Microsoft Windows 10 Version 21H1 | >= 10.0.0 and < 10.0.19043.1052Vendor says fixed in: not stated | |
| Microsoft Windows 7 | >= 6.1.0 and < 6.1.7601.25632Vendor says fixed in: not stated | |
| Microsoft Windows 7 Service Pack 1 | >= 6.1.0 and < 6.1.7601.25632Vendor says fixed in: not stated | |
| Microsoft Windows 8.1 | >= 6.3.0 and < 6.3.9600.20045>= 6.3.0 and < 6.3.9600.20044Vendor says fixed in: not stated | |
| Microsoft Windows Server 2008 R2 Service Pack 1 | >= 6.1.0 and < 6.1.7601.25632Vendor says fixed in: not stated | |
| Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) | >= 6.0.0 and < 6.1.7601.25632Vendor says fixed in: not stated | |
| Microsoft Windows Server 2008 Service Pack 2 | >= 6.0.0 and < 6.0.6003.21137Vendor says fixed in: not stated | |
| Microsoft Windows Server 2008 Service Pack 2 | >= 6.0.0 and < 6.0.6003.21137Vendor says fixed in: not stated | |
| Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) | >= 6.0.0 and < 6.0.6003.21137Vendor says fixed in: not stated | |
| Microsoft Windows Server 2012 | >= 6.2.0 and < 6.2.9200.23372Vendor says fixed in: not stated | |
| Microsoft Windows Server 2012 R2 | >= 6.3.0 and < 6.3.9600.20045>= 6.3.0 and < 6.3.9600.20044Vendor says fixed in: not stated | |
| Microsoft Windows Server 2012 R2 (Server Core installation) | >= 6.3.0 and < 6.3.9600.20045>= 6.3.0 and < 6.3.9600.20044Vendor says fixed in: not stated | |
| Microsoft Windows Server 2012 (Server Core installation) | >= 6.2.0 and < 6.2.9200.23372Vendor says fixed in: not stated | |
| Microsoft Windows Server 2016 | >= 10.0.0 and < 10.0.14393.4467Vendor says fixed in: not stated | |
| Microsoft Windows Server 2016 (Server Core installation) | >= 10.0.0 and < 10.0.14393.4467Vendor says fixed in: not stated | |
| Microsoft Windows Server 2019 | >= 10.0.0 and < 10.0.17763.1999Vendor says fixed in: not stated | |
| Microsoft Windows Server 2019 (Server Core installation) | >= 10.0.0 and < 10.0.17763.1999Vendor says fixed in: not stated | |
| Microsoft Windows Server version 2004 | >= 10.0.0 and < 10.0.19041.1052Vendor says fixed in: not stated | |
| Microsoft Windows Server version 20H2 | >= 10.0.0 and < 10.0.19042.1052Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- microsoft:windows_10_1507
- microsoft:windows_10_1607
- microsoft:windows_10_1809
- microsoft:windows_10_1909
- microsoft:windows_10_2004
- microsoft:windows_10_20h2
- microsoft:windows_10_21h1
- microsoft:windows_7
- microsoft:windows_8.1
- microsoft:windows_rt_8.1
- microsoft:windows_server_2004
- microsoft:windows_server_2008
- microsoft:windows_server_2012
- microsoft:windows_server_2016
- microsoft:windows_server_2019
- microsoft:windows_server_20h2
Fix and mitigation
WAF and other mitigations
Can a WAF block it? No. The attack needs local access to the machine, so a WAF is not on its path.
Also consider: patch
Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 3 Nov 2021.
- CISA due date
- 17 Nov 2021, the remediation deadline for US federal agencies
- CISA required action
- Apply updates per vendor instructions.
- Public exploit code
- None on record in Exploit-DB, Metasploit, Nuclei templates or PoC-in-GitHub.
- CISA SSVC
- exploitation active, automatable no, technical impact partialAssessed by CISA 4 Feb 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Timeline
- 8 Jun 2021Published
- 3 Nov 2021Added to CISA KEV (exploited in the wild)147 days (about 5 months) later
- 17 Nov 2021CISA remediation due date (US federal agencies)14 days later
- 4 Feb 2025CISA SSVC assessment: exploitation active1,176 days (about 3 years) later
- 21 Oct 2025CVE record last updated259 days (about 9 months) later
- 12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
| Metric | Value | What it means |
|---|---|---|
| Attack vector | LocalLocal access required (shell, logged-in user). | Local access required (shell, logged-in user). |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | LowThe attacker needs basic user privileges. | The attacker needs basic user privileges. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | ChangedImpact crosses a security boundary into other components. | Impact crosses a security boundary into other components. |
| Confidentiality | LowPartial data disclosure. | Partial data disclosure. |
| Integrity | LowLimited modification possible. | Limited modification possible. |
| Availability | NoneThe service stays up. | The service stays up. |
Common questions
Is CVE-2021-31201 being exploited?
Yes. CVE-2021-31201 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2021-31201?
CVE-2021-31201 is rated Medium with a CVSS score of 5.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2021-31201?
Yes. A fix has been recorded for CVE-2021-31201. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2021-31201 affect?
CVE-2021-31201 affects microsoft:windows_10_1507, microsoft:windows_10_1607, microsoft:windows_10_1809, microsoft:windows_10_1909, and 12 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
2 references in the CVE record, grouped by the tags the record gives them.
Other links (2)
- portal.msrc.microsoft.com /en-US/security-guidance/advisory/CVE-2021-31201
- cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31201
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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