CVE-2025-3875

Sender Spoofing via Malformed From Header in Thunderbird

CVSS 7.5 HIGHEPSS 0.3%CWE-290

Vexday Risk Score

21Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 7.5EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

14 May 2025Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used. For example, if the From header contains an (invalid) value "Spoofed Name ", Thunderbird treats spoofed@example.com as the actual address. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.

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

Affected products

Mozilla · Thunderbird

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References

https://bugzilla.mozilla.org/show_bug.cgi?id=1950629 https://lists.debian.org/debian-lts-announce/2025/05/msg00022.html https://www.mozilla.org/security/advisories/mfsa2025-34/https://www.mozilla.org/security/advisories/mfsa2025-35/