Process Isolation Vulnerability in Firefox and Thunderbird
CVE-2025-4083
What is CVE-2025-4083?
A process isolation vulnerability in Firefox and Thunderbird arises from improper handling of javascript: URIs. This flaw allows content to potentially execute in the top-level document's process rather than within its intended frame, posing a risk of sandbox escape. Affected versions include Firefox versions prior to 138, Firefox ESR versions before 128.10 and 115.23, as well as Thunderbird versions prior to 138 and its ESR counterpart under 128.10. Users are advised to update to mitigate the risk.

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Affected Version(s)
Firefox < 138
Firefox ESR < 128.10
Firefox ESR < 115.23
References
CVSS V3.1
Timeline
Vulnerability published
Vulnerability Reserved