CVE-2026-40418

Description

Use after free in Microsoft Office Click-To-Run 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)

No configuration data available.

Microsoft Office Click-To-Run (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

#include <iostream>
#include <memory>

// Conceptual PoC for Use-After-Free in C++

class VulnerableObject {
public:
    void printMessage() {
        std::cout << "Object is active." << std::endl;
    }
    virtual ~VulnerableObject() {}
};

int main() {
    // Step 1: Allocate object
    VulnerableObject* obj = new VulnerableObject();
    obj->printMessage();

    // Step 2: Free object (Simulating the vulnerable cleanup)
    delete obj;
    std::cout << "Object freed." << std::endl;

    // Step 3: Use-After-Free (Vulnerability Trigger)
    // In a real exploit, this memory might be reallocated by attacker-controlled data.
    // Accessing the dangling pointer leads to undefined behavior or code execution.
    obj->printMessage(); 

    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-40418
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-40418
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-40418/
[4] VulDB https://vuldb.com/cve/CVE-2026-40418
[5] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40418

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-40418", "sourceIdentifier": "[email protected]", "published": "2026-05-12T18:17:19.940", "lastModified": "2026-05-13T15:34:52.573", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Use after free in Microsoft Office Click-To-Run allows an authorized attacker to elevate privileges locally."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "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": "Primary", "description": [{"lang": "en", "value": "CWE-416"}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40418", "source": "[email protected]"}]}}