CVE-2025-4083

Name: CVE-2025-4083
Creator: NVD / NIST
Published: 2025-04-29T14:15:35.003+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 0.36%

Last modified Jun 17, 2026

CVE-2025-4083 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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.. EPSS estimates a 0.36% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Probability

0.36%

28.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-653

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 115.23
Mozilla	Firefox	< 138.0
Mozilla	Firefox	>= 128.0, < 128.10
Mozilla	Thunderbird	< 128.10.0
Mozilla	Thunderbird	< 138.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1958350Permissions Required
https://www.mozilla.org/security/advisories/mfsa2025-28/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-29/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-30/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-31/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-32/Vendor Advisory
https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html

Timeline

Published: Apr 29, 2025
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2025-4083?

How severe is CVE-2025-4083?

CVE-2025-4083 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.36% probability of exploitation in the next 30 days.

How do I fix CVE-2025-4083?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-4083?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST