CVE-2025-4086

Specially crafted filename could be used to obscure download type

CVSS 6.5 MEDIUMEPSS 0.2%CWE-451

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.5EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

29 Apr 2025Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

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

Affected products

Mozilla · Firefox Mozilla · Thunderbird

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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/