Vulnerability Description
Same-origin policy bypass in the DOM: Service Workers component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
CVSS Score
9.1
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 153.1.0 |
| Mozilla | Thunderbird | < 153.1.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2032406Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-74/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-77/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-78/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-80/Vendor Advisory
FAQ
What is CVE-2026-74956?
CVE-2026-74956 is a vulnerability with a CVSS score of 9.1 (CRITICAL). Same-origin policy bypass in the DOM: Service Workers component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
How severe is CVE-2026-74956?
CVE-2026-74956 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-74956?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird.