CVE-2026-47288: Windows Server 2012 RCE Vulnerability

CVE-2026-47288 Overview

CVE-2026-47288 is an integer overflow vulnerability in the Windows Kerberos authentication component. An authorized attacker on an adjacent network can trigger the flaw to execute arbitrary code on affected systems. The weakness is categorized under [CWE-190] Integer Overflow or Wraparound.

Microsoft published the advisory on June 9, 2026, and the issue affects supported Windows Server releases from 2012 through 2025. Successful exploitation impacts confidentiality, integrity, and availability of the targeted host, making Kerberos-dependent infrastructure such as domain controllers a primary concern.

Critical Impact

Successful exploitation grants code execution within the Kerberos service context, potentially compromising authentication infrastructure across the affected domain.

Affected Products

• Microsoft Windows Server 2012 and 2012 R2
• Microsoft Windows Server 2016, 2019, and 2022
• Microsoft Windows Server 2025 (x64)

Discovery Timeline

• 2026-06-09 - CVE-2026-47288 published to NVD
• 2026-06-10 - Last updated in NVD database

Technical Details for CVE-2026-47288

Vulnerability Analysis

The vulnerability resides in the Windows Kerberos implementation, which handles authentication ticket processing for Active Directory environments. An integer overflow occurs during the parsing or length calculation of Kerberos protocol data. When the calculated value wraps past the maximum integer boundary, the code allocates an undersized buffer or miscomputes a memory offset.

Subsequent operations write attacker-controlled data outside the intended bounds. This memory corruption can be steered into arbitrary code execution within the Kerberos service. Because Kerberos typically runs with high privileges on domain controllers, successful exploitation provides a path to compromise authentication infrastructure.

Exploitation requires authenticated access and adjacent network positioning, such as the same broadcast domain or VLAN as the target. Attack complexity is high, indicating that specific timing or environmental conditions must be met. EPSS data published on June 11, 2026, indicates a probability of 0.322%.

Root Cause

The root cause is an arithmetic operation in Kerberos message handling that does not validate operand ranges before computing buffer sizes or offsets. The unchecked calculation wraps around when supplied with crafted field lengths, producing an incorrect allocation size that later contradicts the actual data copy length.

Attack Vector

An authenticated adversary on an adjacent network segment sends crafted Kerberos traffic to a vulnerable server. The malformed protocol fields trigger the integer wraparound during ticket or message processing. No user interaction is required on the target. See the Microsoft Security Update CVE-2026-47288 advisory for protocol-level technical details.

Detection Methods for CVE-2026-47288

Indicators of Compromise

• Unexpected crashes or restarts of the lsass.exe process on domain controllers, which hosts Kerberos functionality.
• Anomalous Kerberos traffic patterns originating from non-standard hosts within the same subnet as domain controllers.
• Windows Error Reporting entries referencing Kerberos modules such as kerberos.dll or kdcsvc.dll.

Detection Strategies

• Monitor Windows Event Log channels for Kerberos service errors, authentication anomalies, and KDC failures (Event IDs 4769, 4771, 4625).
• Inspect network traffic to TCP/UDP port 88 for malformed Kerberos ASN.1 structures and oversized field lengths.
• Correlate authentication events with process integrity telemetry from endpoint sensors on domain controllers.

Monitoring Recommendations

• Apply behavioral analytics to authentication services to identify deviations from baseline Kerberos request patterns.
• Alert on memory corruption signatures or unexpected child processes spawned by lsass.exe.
• Track lateral movement attempts that follow Kerberos service anomalies, which may indicate post-exploitation activity.

How to Mitigate CVE-2026-47288

Immediate Actions Required

• Apply the Microsoft security update for CVE-2026-47288 to all affected Windows Server systems, prioritizing domain controllers.
• Inventory all Windows Server 2012 through 2025 hosts and confirm patch deployment status across the environment.
• Restrict adjacent network access to domain controllers using network segmentation and host-based firewall rules.

Patch Information

Microsoft has released security updates addressing this vulnerability. Refer to the Microsoft Security Update CVE-2026-47288 for the cumulative update applicable to each Windows Server version. Patches should be applied through Windows Update, WSUS, or your enterprise patch management system.

Workarounds

• Isolate domain controllers on dedicated VLANs and enforce strict ACLs that limit Kerberos traffic to legitimate clients.
• Disable unused authentication protocols and reduce the attack surface exposed to non-administrative workstations.
• Enforce multi-factor authentication and tiered administration to limit the value of any compromised account used to reach adjacent networks.

# Verify installed Kerberos-related security updates on Windows Server
Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 20

# Confirm running version of the Kerberos module
Get-Item C:\Windows\System32\kerberos.dll | Select-Object VersionInfo