How severe is CVE-2025-21309?

CVE-2025-21309 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-21309 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 15% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-21309?

CVE-2025-21309 primarily affects Microsoft Windows Server 2012. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-21309?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-21309 have an EU (EUVD) identifier?

Yes. CVE-2025-21309 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-2374.

When was CVE-2025-21309 published?

CVE-2025-21309 was published on 2025-01-14 and last updated on 2026-06-17.

CVE-2025-21309

CVE-2025-21309 is a high-severity vulnerability in Microsoft Windows Server 2012 with a CVSS 3.x base score of 8.1. Its EPSS exploit-prediction score of 15% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-591.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 15% (96th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-2374
Weakness: CWE-591
Affected product: Microsoft Windows Server 2012
Published: 2025-01-14
Last modified: 2026-06-17

Description

Windows Remote Desktop Services Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2025-21309?: Windows Remote Desktop Services Remote Code Execution Vulnerability
How severe is CVE-2025-21309?: CVE-2025-21309 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-21309 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 15% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-21309?: CVE-2025-21309 primarily affects Microsoft Windows Server 2012. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-21309?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-21309 have an EU (EUVD) identifier?: Yes. CVE-2025-21309 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-2374.
When was CVE-2025-21309 published?: CVE-2025-21309 was published on 2025-01-14 and last updated on 2026-06-17.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21309

Affected products (7)

cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*

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