Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local attacker with an existing low-privilege account (AV:L/PR:L) abuses link following without user interaction to reach SYSTEM, yielding full C/I/A impact within an unchanged scope.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
Improper link resolution before file access ('link following') in Windows Routing and Remote Access Service (RRAS) allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows Routing and Remote Access Service (RRAS) lets an already-authenticated low-privileged user (PR:L) abuse a symbolic-link/junction resolution flaw (CWE-59) to redirect a privileged file operation and gain SYSTEM-level control on affected Windows 10, Windows 11, and Windows Server 2012-2025 hosts. Microsoft has released patches; there is no public exploit identified at time of analysis and the flaw is not in CISA KEV, with a low EPSS of 0.28% (20th percentile). SSVC rates technical impact as total but marks exploitation as none and not automatable, consistent with a hands-on local escalation rather than a mass-exploitable remote bug.
Technical ContextAI
RRAS is the Windows service that provides routing, dial-up/VPN remote access, and NAT functionality, running with high privilege as part of the OS networking stack. The root cause is CWE-59, improper link resolution before file access ('link following'): the service accesses a file by path without safely validating that the path has not been redirected through a symbolic link, junction, or hard link controlled by a lower-privileged user. When a privileged process follows such an attacker-planted link, it can be tricked into writing to, creating, or overwriting a file the attacker could not otherwise touch, converting the service's privileges into arbitrary file operations. The CPE data confirms the affected components are Microsoft OS builds spanning Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2012 through 2025, including Server Core installations.
RemediationAI
Apply the Microsoft security update for CVE-2026-49791 via the standard monthly cumulative update, referenced at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49791 - Vendor-released patch: install at least the fixed build for your OS (for example 10.0.19045.7548 for Windows 10 22H2, 10.0.26100.8875 for Windows 11 24H2, 10.0.20348.5386 for Windows Server 2022, or 10.0.26100.33158 for Windows Server 2025). Because exploitation requires the RRAS service, hosts that do not need routing/VPN/dial-up should disable and stop the Routing and Remote Access service (services.msc / Stop-Service RemoteAccess), which removes the attack surface entirely with the trade-off of losing any RRAS-provided VPN, NAT, or routing on that machine. Where the service must run and patching is delayed, reduce the population of local low-privilege users on the affected host (e.g., on servers restrict interactive/console logon rights) since exploitation depends on an existing local foothold; this does not fix the flaw and only shrinks the attacker pool. Prioritize multi-user and Server Core systems and confirm the build number after patching.
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Same weakness CWE-59 – Improper Link Resolution Before File Access
View allSame technique Information Disclosure
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-43806
GHSA-6v4x-m393-5vg2