CVE-2025-4083
Process isolation bypass using "javascript:" URI links in cross-origin frames
9.1CVSSCRITICAL
Description
A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.
CVSS Vector Breakdown
Exploitability
AV:NAttack VectorNetwork
AC:LAttack ComplexityLow
PR:NPrivileges RequiredNone
UI:NUser InteractionNone
Scope
S:UScopeUnchanged
Impact
C:HConfidentialityHigh
I:HIntegrityHigh
A:NAvailabilityNone
Weaknesses
Affected Products
and 15 more affected products View all →
Exploitability
Official Patch Available
References
https://bugzilla.mozilla.org/show_bug.cgi?id=1958350
bugzilla.mozilla.org
https://www.mozilla.org/security/advisories/mfsa2025-28/
mozilla.org
https://www.mozilla.org/security/advisories/mfsa2025-29/
mozilla.org
and 13 more references View all →
Timeline
Published
Apr 29, 2025
Last Updated
Apr 13, 2026
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