CVE-2026-69852

CVE-2026-69852 is a heap-based buffer overflow (CWE-122) in the Windows Routing and Remote Access Service (RRAS) that allows remote code execution, letting an attacker gain unauthorized access to the victim's machine. Per the CVSS vector, the flaw is reachable over the network (AV:N) but requires low privileges (PR:L) — i.e., some degree of valid access to the RRAS-enabled host — and is rated high attack complexity (AC:H), making successful exploitation non-trivial. Attackers who exploit it gain code execution on the target, with high impact on confidentiality, integrity, and availability. Exposure is limited to Windows systems where RRAS is enabled, typically Windows Server machines configured as routers, NAT gateways, or VPN endpoints; Microsoft addressed the issue in the September 2026 Patch Tuesday security updates. There is currently no known public proof-of-concept, the CVE is not in CISA KEV, and EPSS puts 30-day exploitation probability at just 0.6% (48th percentile), indicating no observed exploitation activity so far.

What to do: Prioritize applying Microsoft's September 2026 security updates on any host with the Routing and Remote Access service or role enabled — inventory Windows Servers acting as VPN concentrators, NAT gateways, or routers first. Until patched, restrict network access to RRAS endpoints to trusted networks and audit which low-privileged accounts can reach the service, since exploitation requires network reachability plus some valid access. Monitor vendor advisories for the corrected build numbers applicable to your Windows versions.