CVE-2025-4083

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

Severity Score

9.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

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.

This update for MozillaFirefox fixes the following issues. Firefox Extended Support Release 128.10.0 ESR MFSA 2025-29. Potential privilege escalation in Firefox Updater WebGL shader attribute memory corruption in Firefox for macOS Process isolation bypass using 'javascript:' URI links in cross-origin frames. Potential local code execution in "copy as cURL" command Unsafe attribute access during XPath parsing. Memory safety bugs fixed in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10. Memory safety bug fixed in Firefox ESR 128.10 and Thunderbird 128.10.

*Credits: Nika Layzell

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

Low

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

Complete

Integrity

Complete

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Total

* Organization's Worst-case Scenario

Timeline

2025-04-29 CVE Reserved
2025-04-29 CVE Published
2025-05-07 CVE Updated
2025-07-06 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-653: Improper Isolation or Compartmentalization

CAPEC

References (8)

URL	Tag	Source
https://bugzilla.mozilla.org/show_bug.cgi?id=1958350
https://www.mozilla.org/security/advisories/mfsa2025-28
https://www.mozilla.org/security/advisories/mfsa2025-29
https://www.mozilla.org/security/advisories/mfsa2025-30
https://www.mozilla.org/security/advisories/mfsa2025-31
https://www.mozilla.org/security/advisories/mfsa2025-32

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2025-4083	2025-05-15
https://bugzilla.redhat.com/show_bug.cgi?id=2362907	2025-05-15

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Mozilla Search vendor "Mozilla"		Firefox Search vendor "Mozilla" for product "Firefox"				*		-		Affected
Mozilla Search vendor "Mozilla"		Firefox Esr Search vendor "Mozilla" for product "Firefox Esr"				*		-		Affected
Mozilla Search vendor "Mozilla"		Thunderbird Search vendor "Mozilla" for product "Thunderbird"				*		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				*		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				*		-		Affected
Slackware Search vendor "Slackware"		Slackware Linux Search vendor "Slackware" for product "Slackware Linux"				*		-		Affected