CVE-2026-8955

Description

Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.

CVSS Details

CVSS Score

6.5

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

Firefox < 151

Firefox ESR < 140.11

PoC / Exploit Code

⚠ For Security Research Only

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

python

<!--
PoC Concept for CVE-2026-8955
This script demonstrates the potential triggering of the DOM Workers vulnerability.
-->

<!DOCTYPE html>
<html>
<head>
    <title>CVE-2026-8955 PoC</title>
</head>
<body>
<script>
    // Create a malicious worker blob to exploit the privilege escalation
    const exploitCode = `
        self.onmessage = function(e) {
            // Attempt to access restricted resources or escalate privileges
            try {
                // Hypothetical exploitation logic
                postMessage("Exploitation Attempt Triggered");
            } catch (err) {
                postMessage("Error: " + err.message);
            }
        };
    `;
    
    const blob = new Blob([exploitCode], {type: 'application/javascript'});
    const workerUrl = URL.createObjectURL(blob);
    const worker = new Worker(workerUrl);
    
    worker.onmessage = function(e) {
        console.log("[CVE-2026-8955] Worker Response:", e.data);
    };
    
    // Trigger the worker
    worker.postMessage("start");
</script>
</body>
</html>

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-8955
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-8955
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-8955/
[4] VulDB https://vuldb.com/cve/CVE-2026-8955
[5] https://bugzilla.mozilla.org/show_bug.cgi?id=2031064
[6] https://www.mozilla.org/security/advisories/mfsa2026-46/
[7] https://www.mozilla.org/security/advisories/mfsa2026-48/

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-8955", "sourceIdentifier": "[email protected]", "published": "2026-05-19T14:16:51.820", "lastModified": "2026-05-19T15:16:34.827", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11."}], "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:L/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 2.5}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-269"}]}], "references": [{"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2031064", "source": "[email protected]"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-46/", "source": "[email protected]"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-48/", "source": "[email protected]"}]}}