Cyber Resilience

CVE-2025-4083

Critical

Published: 29 April 2025

Published
29 April 2025
Modified
13 April 2026
KEV Added
Patch
CVSS Score v3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0022 44.9th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-4083 is a critical-severity Improper Isolation or Compartmentalization (CWE-653) vulnerability in Mozilla Firefox. Its CVSS base score is 9.1 (Critical).

Operationally, ranked at the 44.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

mozilla
firefox
≤ 115.23 · ≤ 138.0 · 128.0 — 128.10
mozilla
thunderbird
≤ 128.10.0 · ≤ 138.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-653

Defines isolation boundaries by specifying which external systems may access or process organization data.

addresses: CWE-653

Maintains isolation and compartmentalization by restricting flows between security domains or levels.

addresses: CWE-653

Reviewing the continued need for connections supports isolation and compartmentalization.

addresses: CWE-653

Locating systems away from hazards improves isolation and compartmentalization from external physical or environmental threats.

addresses: CWE-653

The CONOPS must articulate isolation and compartmentalization expectations for security and privacy, making architectural failures in separation of duties or domains harder to overlook.

addresses: CWE-653

Security architectures commonly incorporate isolation and compartmentalization strategies to limit the impact of compromises.

addresses: CWE-653

Organization-wide privacy program leadership ensures proper isolation and compartmentalization of personal data.

addresses: CWE-653

Oversight ensures data-matching activities maintain required isolation between distinct data sets and authorized user communities.

References