CVE-2026-12304 | Same-origin policy bypass in the Networking: Cookies compone… | CVSS 9.1 CRITICAL

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.

Metadata

CVE ID: CVE-2026-12304
State: PUBLISHED
Assigner: mozilla
Reserved: 2026-06-15 15:08 UTC
Published: 2026-06-16 11:52 UTC
Last updated: 2026-06-16 18:55 UTC
Primary CWE: CWE-346
CWE-346 Origin Validation Error
Vendor / Product: Mozilla / Firefox
Sources: cve.org · NVD

Severity & Metrics

9.1 CRITICAL CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: total

Affected products (2)

Vendor	Product	Platform	Versions
Mozilla	Firefox	—	140.12 ≤ 140., 152 ≤
Mozilla	Thunderbird	—	140.12 ≤ 140., 152 ≤

Weakness (CWE)

CWE	Source	Description
CWE-346	adp	CWE-346 Origin Validation Error

CVSS scores (1)

Score	Severity	Version	Source	Vector
9.1	CRITICAL	3.1	adp	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References (5)