Medium severity6.5NVD Advisory· Published Apr 29, 2025· Updated Apr 13, 2026

CVE-2025-4086

Description

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.

Affected products

Mozilla Corporation/Firefox
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
Range: <138.0
Mozilla Corporation/Thunderbird
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
Range: <138.0

Patches

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

www.mozilla.org/security/advisories/mfsa2025-28/nvdVendor Advisory
www.mozilla.org/security/advisories/mfsa2025-31/nvdVendor Advisory
bugzilla.mozilla.org/show_bug.cginvdPermissions Required

News mentions

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cvss	0.423
epss	0.000
exploit	0.000
kev	0.000
patch	0.000
ransomware	0.000