Patch tracker / CVE reference / CVE-2025-21329
CVE-2025-21329
Critical severity Microsoft vulnerability, CVSS 9.8. Fixed by 13 Microsoft security updates.
All about CVE-2025-21329: the Senserva AI read, whether it is exploited, the official patches, its change history, and the questions admins ask.
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CVE-2025-21329 is a critical severity Microsoft vulnerability with a CVSS score of 9.8. Its EPSS score puts the probability of exploitation in the next 30 days at 81%. Microsoft has shipped the fix: deploy one of the 13 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
Risk summary
Senserva AI Opinion for CVE-2025-21329
This MapUrlToZone security feature bypass, Critical at CVSS 9.8 with 81 percent EPSS, reaches Windows Server 2025, Windows Server 2025 Server Core, and Windows 10 Version 1809. It is one of several nearly identical zone-bypass bugs patched together, underscoring that MapUrlToZone had a cluster of distinct flaws fixed in the same cycle.
Do this: Confirm this MapUrlToZone CVE is patched on Windows Server 2025 systems in addition to the other related fixes.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2025-21329
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2025-21329
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 81%. CVSS 9.8 (Critical).
This CVE is among the top 25% of tracked Microsoft CVEs by EPSS exploit probability.
Official patch(es) for CVE-2025-21329
High priority: EPSS puts the odds of near-term exploitation high. In Intune or Defender, confirm whether the fixing updates KB5049981, KB5049983, KB5049984, KB5049993, KB5049994, KB5050004, KB5050008, KB5050009, KB5050013, KB5050021, KB5050048, KB5050049, KB5050063 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-2025-21329. Each KB page links to the Microsoft Update Catalog download for every affected product.
Affected products
Common questions about CVE-2025-21329
Is CVE-2025-21329 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 81%.
What patch fixes CVE-2025-21329?
Microsoft fixed CVE-2025-21329 in KB5049981, KB5049983, KB5049984, KB5049993, KB5049994, KB5050004, KB5050008, KB5050009, KB5050013, KB5050021, KB5050048, KB5050049, KB5050063. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.
Which products are affected by CVE-2025-21329?
Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019, Windows Server 2025, Windows Server 2025 (Server Core installation).
Can I ask my own AI about CVE-2025-21329?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2025-21329'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-2025-21329, 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.
