CVE-2025-4083 — Improper Isolation or Compartmentalization in Mozilla Firefox

CWE-653 — Improper Isolation or Compartmentalization12 documents8 sources
Severity
9.1CRITICALNVD
EPSS
0.4%
top 38.89%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla ThunderbirdMozilla Firefox
Timeline
PublishedApr 29
Latest updateJul 22

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NExploitability: 3.9 | Impact: 5.2

Affected Packages3 packages

▶NVDmozilla/firefox128.0 — 128.10+2
▶NVDmozilla/thunderbird< 128.10.0+1
▶Debianmozilla/thunderbird< 1:128.10.1esr-1~deb11u1+3

🔴Vulnerability Details

3
GHSA
GHSA-v4qx-h7r5-6qc8: A process isolation vulnerability in Firefox stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level↗2025-04-29
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OSV
CVE-2025-4083: A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-l↗2025-04-29
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CVEList
Process isolation bypass using "javascript:" URI links in cross-origin frames↗2025-04-29
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📋Vendor Advisories

8
Ubuntu
Thunderbird vulnerabilities↗2025-07-22
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Red Hat
firefox: thunderbird: Process isolation bypass using "javascript:" URI links in cross-origin frames↗2025-04-29
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Debian
CVE-2025-4083: firefox - A process isolation vulnerability in Thunderbird stemmed from improper handling ...↗2025
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Mozilla
Mozilla Foundation Security Advisory 2025-31: CVE-2025-4083↗
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Mozilla
Mozilla Foundation Security Advisory 2025-32: CVE-2025-4083↗
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CVE-2025-4083 — Mozilla Firefox vulnerability | cvebase