Is CVE-2025-21309 in the CISA KEV catalog?

No. CVE-2025-21309 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2025-21309?

CVE-2025-21309 has a CVSS v3 base score of 8.1 (HIGH).

What is the EPSS score for CVE-2025-21309?

CVE-2025-21309 has an EPSS score of 14.98% (96th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2025-21309?

Install KB5050004 for Windows Server 2012. Fixes are available for 13 affected products.

CVE & CISA-KEV Catalog

CVE-2025-21309

HIGHEPSS 96th pctl

8.1

CVSS v3

NVD

Description

Windows Remote Desktop Services Remote Code Execution Vulnerability

CWE-591

How to fix

Remediation Available

Windows Server 2012Windows

Install:KB5050004Microsoft

Windows Server 2012 (Server Core installation)Windows

Install:KB5050004Microsoft

Windows Server 2012 R2Windows

Install:KB5050048Microsoft

Windows Server 2012 R2 (Server Core installation)Windows

Install:KB5050048Microsoft

Windows Server 2016Windows

Install:KB5049993Microsoft

Windows Server 2016 (Server Core installation)Windows

Install:KB5049993Microsoft

Windows Server 2019Windows

Install:KB5050008Microsoft

Windows Server 2019 (Server Core installation)Windows

Install:KB5050008Microsoft

Windows Server 2022Windows

Install:KB5049983Microsoft

Windows Server 2022 (Server Core installation)Windows

Install:KB5049983Microsoft

Windows Server 2022, 23H2 Edition (Server Core installation)Windows

Install:KB5049984Microsoft

Windows Server 2025Windows

Install:KB5050009Microsoft

Windows Server 2025 (Server Core installation)Windows

Install:KB5050009Microsoft

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

14.98%probability of exploitation in 30 days

96thpercentile

Very high risk: more likely to be exploited than 96% of all known CVEs.

References

Patch1

msrc.microsoft.com

Related Vulnerabilities

Other CWE-591 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-36005	High	7.5	24%	-	Fix
CVE-2025-30394	Medium	5.9	21%	-	Fix
CVE-2023-28220	High	8.1	15%	-	Fix
CVE-2023-28219	High	8.1	15%	-	Fix
CVE-2024-38106	High	7.0	6.3%	KEV	Fix
CVE-2023-38159	High	7.0	5.6%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-01-24.