CVE-2025-4083: firefox — Fix

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.

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CVSS v3.1 Score

9.1

CRITICAL

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

Weakness Type (CWE)

CWE-653 CWE-653

Affected Products

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

Advisories & Patches

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/

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=1958350 https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html

Frequently Asked Questions

What is 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-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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2025-4083? +

CVE-2025-4083 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2025-4083? +

CVE-2025-4083 affects products from mozilla, specifically: firefox, thunderbird. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-4083? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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