CVE-2025-4086

EUVD-2025-12656
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 in Firefox 138 and Thunderbird 138.
UI
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mozillaCNA
6.5 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 20.14%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mozillafirefox
𝑥
< 138.0
CNA
mozillathunderbird
𝑥
< 138.0
CNA
Debian logo
Debian Releases
Debian Product
Codename
firefox
sid
157.0.1-1
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
firefox
focal
dne
jammy
not-affected
noble
not-affected
oracular
not-affected
plucky
not-affected
thunderbird
focal
dne
jammy
not-affected
noble
not-affected
oracular
not-affected
plucky
not-affected
Common Weakness Enumeration
References
https://bugzilla.mozilla.org/show_bug.cgi?id=1945705
https://www.mozilla.org/security/advisories/mfsa2025-28/
https://www.mozilla.org/security/advisories/mfsa2025-31/