Cyber Resilience

CVE-2025-21218

DoS in Microsoft Windows Server 2012 r2

Published
14 January 2025
Modified
27 January 2025
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.026 84th percentile
Risk Priority 63 floored blend · peak EPSS

Summary

CVE-2025-21218 is a high-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Microsoft Windows Server 2012. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique OS Exhaustion Flood (T1499.001); ranked in the top 16% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SC-5 (Denial-of-service Protection) and SC-6 (Resource Availability) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-21218 is a denial-of-service vulnerability in the Windows Kerberos implementation, tracked under CWE-400. It affects the Kerberos authentication component in Windows and is rated 7.5 CVSS:3.1 with a vector that reflects network attackability, low complexity, and no required privileges or user interaction, resulting in high availability impact while leaving confidentiality and integrity untouched.

An unauthenticated remote attacker can send crafted traffic to trigger uncontrolled resource consumption in the Kerberos service, causing a denial-of-service condition that disrupts authentication for affected systems. No prior access or credentials are needed, allowing the flaw to be reached directly over the network.

The Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21218 supplies patch information and mitigation guidance. EPSS probability has climbed from a low baseline to a recorded peak of 0.0332, indicating that exploitation interest increased after disclosure.

EU & UK References

Vulnerability Data

Windows Kerberos Denial of Service Vulnerability

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499.001 OS Exhaustion Flood Impact
Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS).
T1498 Network Denial of Service Impact
Adversaries may perform Network Denial of Service (DoS) attacks to degrade or block the availability of targeted resources to users.
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.002 Service Exhaustion Flood Impact
Adversaries may target the different network services provided by systems to conduct a denial of service (DoS).
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-26652Same product: Microsoft Windows Server 2012
CVE-2025-27485Same product: Microsoft Windows Server 2012
CVE-2025-21174Same product: Microsoft Windows Server 2012
CVE-2025-27486Same product: Microsoft Windows Server 2012
CVE-2024-38015Same product: Microsoft Windows Server 2012
CVE-2025-26680Same product: Microsoft Windows Server 2012
CVE-2025-33068Same product: Microsoft Windows Server 2012
CVE-2025-27470Same product: Microsoft Windows Server 2012
CVE-2024-38067Same product: Microsoft Windows Server 2012
CVE-2024-30019Same product: Microsoft Windows Server 2012

Affected Assets

microsoft
windows server 2012
all versions, r2
microsoft
windows server 2016
≤ 10.0.14393.7699
microsoft
windows server 2019
≤ 10.0.17763.6775
microsoft
windows server 2022
≤ 10.0.20348.3091
microsoft
windows server 2022 23h2
≤ 10.0.25398.1369
microsoft
windows server 2025
≤ 10.0.26100.2894

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SC-5 directly limits the effects of resource-exhaustion events that constitute uncontrolled consumption.

SC-6 enforces explicit allocation limits on resources, structurally preventing the weakness from occurring.

Process isolation confines resource consumption to separate domains, reducing blast radius without stopping the root flaw.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.IR-04 mostly match
prevents

Explicitly requires monitoring and maintaining resource capacity, directly addressing uncontrolled consumption to preserve availability.

DE.CM-09 partial match
prevents

Continuous monitoring of computing resources can detect resource exhaustion but does not itself enforce allocation limits.

PR.IR-03 partial match
prevents

Resilience mechanisms such as avoiding single points of failure indirectly reduce impact of resource exhaustion.

PR.PS-01 partial match
prevents

Hardened configuration baselines can include resource quotas and limits that constrain consumption.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Resource-utilization monitoring and alerting on bottlenecks or overloads limits the impact of denial-of-service or resource-exhaustion attacks.

prevents

By continuously monitoring utilization, stress-testing peak loads, and maintaining documented plans to scale or throttle resources, the control directly limits an attacker’s ability to drive a system into uncontrolled resource exhaustion.

finds

Pre-agreed severity-based prioritization and resource allocation during incident triage reduce the likelihood that an attacker-induced resource exhaustion will overwhelm the organization before corrective action is taken.

mitigates

Business-continuity plans that include resource-management controls reduce the likelihood that an attacker can trigger uncontrolled resource consumption by forcing the system into a degraded or fallback state.

mitigates

Defining RTOs and capacity requirements for ICT services during business-impact analysis forces organizations to provision sufficient resources and throttling mechanisms, reducing the likelihood that an attacker can induce denial-of-service through uncontrolled resource consumption.

finds

Early notification of anomalous resource consumption or system malfunctions enables throttling or isolation before availability is lost.

References