CVE-2025-4086

Summary

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.

Impact & exploitability

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

Affected products we track (1)

Recommendation

Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.

Additional information

• NVD record
• https://www.mozilla.org/security/advisories/mfsa2025-28/Advisory
• https://www.mozilla.org/security/advisories/mfsa2025-31/Advisory
• https://bugzilla.mozilla.org/show_bug.cgi?id=1945705