Cyber Resilience

CVE-2025-4086

Medium

Published: 29 April 2025

Published
29 April 2025
Modified
13 April 2026
KEV Added
—
Patch
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CVSS Score v3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.0026 49.5th percentile
Risk Priority 13 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-4086 is a medium-severity User Interface (UI) Misrepresentation of Critical Information (CWE-451) vulnerability in Mozilla Firefox. Its CVSS base score is 6.5 (Medium).

Operationally, ranked at the 49.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

A specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog. *This bug only affects Thunderbird for Android. Other versions of Thunderbird are unaffected.*. This vulnerability was fixed…

more

in Firefox 138 and Thunderbird 138.

CWE(s)
CWE-451

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

mozilla
firefox
≤ 138.0
mozilla
thunderbird
≤ 138.0

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References