Windows Remote Desktop Services CVE-2026-69599

The attacker must be an authorized user - holding valid credentials sufficient to establish a Remote Desktop Services session against the target host (PR:L per CVSS). The RDS role or Remote Desktop must be enabled and network-accessible on the target. AC:H indicates that exploitation is not reliable against default configurations without meeting additional preconditions, likely involving heap state manipulation or timing. Limiting factors: unauthenticated exploitation is not possible; the target host must be running an unpatched build of Windows 11 (23H2/24H2/25H2/26H1) or Windows Server 2025; modern Windows exploit mitigations (ASLR, CFG, Heap Metadata Integrity) impose meaningful exploitation difficulty at AC:H; there is no known public exploit at time of analysis.

The CVSS vector AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H yields a score of 7.5, reflecting a meaningful but not trivially exploitable vulnerability. AC:H indicates that successful exploitation requires specific conditions - consistent with UAF exploitation in modern Windows environments, where heap exploitation must contend with ASLR, CFG (Control Flow Guard), and heap metadata integrity checks. PR:L confirms that unauthenticated exploitation is not possible; the attacker must hold a valid RDS session or equivalent network credential. The full C:H/I:H/A:H impact triad signals that successful exploitation results in complete system compromise. No public exploit code has been identified and the CVE is not listed in CISA KEV, so real-world exploitation risk at this time is lower than the impact metrics alone suggest. However, Windows Server 2025 and Windows 11 RDS are high-value targets in enterprise environments, and a working exploit would be highly sought after. The 'Denial Of Service' tag appears to understate the primary impact; the description explicitly confirms code execution.

An attacker with valid domain or local credentials for the target Windows Server 2025 host establishes a Remote Desktop Services session and sends a crafted sequence of protocol messages designed to trigger a race condition or specific allocation/free sequence in the RDS heap, causing the server to reference freed memory. By controlling the freed memory region through heap grooming techniques, the attacker redirects execution flow and runs arbitrary code in the context of the RDS service process. No public exploit code has been identified, but the attack is feasible for a skilled researcher given prior Windows RDP/RDS heap exploitation research.