CVE-2026-74956

CriticalCVSS 9.1/10Last modified Aug 19, 2026

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.

Metrics

CVSS 3.1 9.1/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Weakness enumeration

CWE-843

Affected software

No affected versions have been published.

Timeline

Published
Aug 18, 2026
Last modified
Aug 19, 2026
NVD status
Analyzed

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CVE-2026-74956: Critical severity, CVSS 9.1 | Vulnix