CVE-2025-4083
CRITICALDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 35% of all known CVEs.
References
Related Vulnerabilities
Other CWE-653 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-1974 | Critical | 9.8 | 100% | - | - |
| CVE-2025-57738 | High | 7.2 | 23% | - | Fix |
| CVE-2025-21590 | Medium | 4.4 | 1.7% | KEV | - |
| CVE-2026-24781 | Critical | 9.8 | 1.2% | - | Fix |
| CVE-2024-0135 | High | 7.6 | 1.1% | - | Fix |
| CVE-2026-43997 | Critical | 10.0 | 1.0% | - | Fix |
Common questions
How do I fix CVE-2025-4083?
Published advisories record a fix for 19 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2025-4083 being actively exploited?
Not that we know of. CVE-2025-4083 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.43% is the estimated probability that it will be exploited in the next 30 days. That is higher than 35% of all scored CVEs.
How severe is CVE-2025-4083?
CVE-2025-4083 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2025-4083 affect?
Published advisories record a fix for firefox (Debian), firefox (Rocky), firefox (Red Hat / RHEL), firefox-debuginfo (Rocky), and 15 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-13.