CVE-2025-4083

Process isolation bypass using "javascript:" URI links in cross-origin frames

Published Apr 29, 2025 CVSS 3.1 · 9.1 Critical EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4167-1 thunderbird security update
Debian DLA Debian DLA DLA-4172-1 firefox-esr security update
Debian DSA Debian DSA DSA-5910-1 firefox-esr security update
Debian DSA Debian DSA DSA-5912-1 thunderbird security update
EUVD EUVD EUVD-2025-12730 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 affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.
Ubuntu USN Ubuntu USN USN-7663-1 Thunderbird vulnerabilities
History
Type Values Removed Values Added
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 affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10. 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.
Title firefox: thunderbird: Process isolation bypass using "javascript:" URI links in cross-origin frames Process isolation bypass using "javascript:" URI links in cross-origin frames
Type Values Removed Values Added
First Time appeared Redhat rhel Aus
Redhat rhel Tus
CPEs cpe:/a:redhat:rhel_aus:8.2
cpe:/a:redhat:rhel_aus:8.4
cpe:/a:redhat:rhel_aus:8.6
cpe:/a:redhat:rhel_e4s:8.4
cpe:/a:redhat:rhel_e4s:8.6
cpe:/a:redhat:rhel_eus:8.8
cpe:/a:redhat:rhel_tus:8.4
cpe:/a:redhat:rhel_tus:8.6
Vendors & Products Redhat rhel Aus
Redhat rhel Tus
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10.0
Type Values Removed Values Added
CPEs cpe:/a:redhat:rhel_eus:9.4
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla
Mozilla firefox
Mozilla thunderbird
Type Values Removed Values Added
First Time appeared Redhat rhel E4s
Redhat rhel Els
Redhat rhel Eus
CPEs cpe:/a:redhat:rhel_e4s:9.0
cpe:/a:redhat:rhel_eus:9.2
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel E4s
Redhat rhel Els
Redhat rhel Eus
Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Type Values Removed Values Added
Title firefox: thunderbird: Process isolation bypass using "javascript:" URI links in cross-origin frames
References
Metrics threat_severity

None

threat_severity

Important

Type Values Removed Values Added
Description A process isolation vulnerability in Firefox 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 affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird ESR < 128.10. 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 affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-653
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

Type Values Removed Values Added
Description A process isolation vulnerability in Firefox 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 affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird ESR < 128.10.
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Jul 25, 2026, 1:15 AM
Reserved
Apr 29, 2025, 1:13 PM
Status
Modified
Published
Apr 29, 2025, 2:15 PM
Modified
Oct 5, 2026, 3:10 PM
Severity
Important
Public date
Apr 29, 2025, 1:13 PM