CVE-2026-12294 | Sandbox escape in the DOM: Workers component. This vulnerabi… | CVSS 9.6 CRITICAL

Description

Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

Metadata

CVE ID: CVE-2026-12294
State: PUBLISHED
Assigner: mozilla
Reserved: 2026-06-15 15:08 UTC
Published: 2026-06-16 11:52 UTC
Last updated: 2026-06-18 16:11 UTC
Primary CWE: CWE-693
CWE-693 Protection Mechanism Failure
Vendor / Product: Mozilla / Firefox
Sources: cve.org · NVD

Severity & Metrics

9.6 CRITICAL CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: total

Affected products (2)

Vendor	Product	Platform	Versions
Mozilla	Firefox	—	115.37 ≤ 115., 140.12 ≤ 140., 152 ≤ *
Mozilla	Thunderbird	—	140.12 ≤ 140., 152 ≤

Weakness (CWE)

CWE	Source	Description
CWE-693	adp	CWE-693 Protection Mechanism Failure

CVSS scores (1)

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

References (6)