Patch tracker / CVE reference / CVE-2025-21212
CVE-2025-21212
CVE-2025-21212 is a high severity Microsoft vulnerability with a CVSS score of 8.8. Its EPSS score puts the probability of exploitation in the next 30 days at 24%. Microsoft has shipped the fix: deploy one of the 9 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
High severity Microsoft vulnerability, CVSS 8.8. Fixed by 9 Microsoft security updates.
Risk summary
Updated July 24, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2025-21212
Internet Connection Sharing on these Windows 10 1809 and Server 2019 hosts can be crashed remotely, knocking the shared connection and dependent services offline rather than exposing data. At CVSS 8.8 the impact is rated high because a single request can take down the service, and the 22 percent EPSS score puts it meaningfully above background noise for opportunistic scanning. It has not been added to CISA's Known Exploited Vulnerabilities catalog and is not tied to ransomware campaigns.
Do this: Disable Internet Connection Sharing where it is not actually needed and patch remaining 1809 or Server 2019 hosts that require it.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2025-21212
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2025-21212
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
Exploitation and severity
Not in the CISA KEV catalog. EPSS exploit probability 24%. CVSS 8.8 (High).
This CVE is among the top half of tracked Microsoft CVEs by EPSS exploit probability.
Official patch(es) for CVE-2025-21212
Elevated priority: high severity or a meaningful exploitation probability, sooner if an affected product is internet-facing. In Intune or Defender, confirm whether the fixing updates KB5051974, KB5051979, KB5051980, KB5051987, KB5051989, KB5052000, KB5052006, KB5052105, KB5052106 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.
Apply the Microsoft security updates below to fix CVE-2025-21212. Each KB page carries the Microsoft Update Catalog download, Microsoft's known issues for the update, a copy-paste PowerShell check for whether it is installed, and the Senserva AI read.
Affected products
Common questions about CVE-2025-21212
Is CVE-2025-21212 actively exploited?
It is not currently listed in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score puts the probability of exploitation in the next 30 days at 24%.
What patch fixes CVE-2025-21212?
Microsoft fixed CVE-2025-21212 in KB5051974, KB5051979, KB5051980, KB5051987, KB5051989, KB5052000, KB5052006, KB5052105, KB5052106. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.
Which products are affected by CVE-2025-21212?
Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019.
Can I ask my own AI about CVE-2025-21212?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2025-21212's key facts: severity, CVSS, EPSS exploit probability, CISA KEV status, and the fixing KB. Copy it into Claude, ChatGPT, or Copilot for a triage plan; the data is refreshed three times a day (5 AM, 12:30 PM, and 7 PM US Central).
Fixed by the same updates
If you are patching CVE-2025-21212, the same updates also fix these:
Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.
