CVE-2026-0881

CRITICAL

Firefox and Thunderbird < 147.0 - Sandbox Escape via Messaging System Component

Title source: llm

Sandbox escape in the Messaging System component. This vulnerability was fixed in Firefox 147 and Thunderbird 147.

Core 3

Core References

Permissions Required

Vendor Advisory

Vendor Advisory

CVSS v3 10.0

EPSS 0.0037

EPSS Percentile 29.0%

Attack Vector NETWORK

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

Vulnrichment

Exploitation none

Automatable yes

Technical Impact total

CWE

CWE-284 CWE-693

Status published

Products (4)

mozilla/firefox < 147.0

Mozilla/Firefox 147

mozilla/thunderbird < 147.0

Mozilla/Thunderbird 147

Published Jan 13, 2026

Tracked Since Feb 18, 2026