CVE-2026-74956

critical · 9.1

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.

9.1

CVSS

0.5%

EPSS (exploit prob.)

42nd

EPSS percentile

2026-08-18

Published

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

Weaknesses

CWE-843

Affected products

Vendor	Product	Affected versions
mozilla	firefox	< 153.1.0
mozilla	firefox	< 154.0.0
mozilla	thunderbird	< 153.1.0
mozilla	thunderbird	< 154.0

Check a specific version with /api/v1/cve/match.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2032406
https://www.mozilla.org/security/advisories/mfsa2026-74/
https://www.mozilla.org/security/advisories/mfsa2026-77/
https://www.mozilla.org/security/advisories/mfsa2026-78/
https://www.mozilla.org/security/advisories/mfsa2026-80/

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-74956