CVE-2026-12304

CRITICAL

Same-origin policy bypass in the Networking: Cookies component

Title source: cna

Description

Same-origin policy bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

References (5)

Core 5

Core References

https://bugzilla.mozilla.org/show_bug.cgi?id=2034944

https://www.mozilla.org/security/advisories/mfsa2026-57/

https://www.mozilla.org/security/advisories/mfsa2026-58/

https://www.mozilla.org/security/advisories/mfsa2026-60/

https://www.mozilla.org/security/advisories/mfsa2026-61/

Scores

CVSS v3 9.1

EPSS 0.0019

EPSS Percentile 8.7%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact total

Details

CWE

CWE-346

Status published

Products (8)

mozilla/firefox < 140.12.0

mozilla/firefox < 152.0.0

Mozilla/Firefox 140.12 - 140.*

Mozilla/Firefox 152

mozilla/thunderbird < 140.12.0

mozilla/thunderbird < 152.0.0

Mozilla/Thunderbird 140.12 - 140.*

Mozilla/Thunderbird 152

Published Jun 16, 2026

Tracked Since Jun 16, 2026