Vulnerability in Mozilla Thunderbird

CVE-2025-3875

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@exa…

EPSS: 0.003 (23.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-3875?
CVE-2025-3875 is a high-severity vulnerability in Mozilla Thunderbird, classified under Authentication Bypass by Spoofing. CVSS score: 7.5/10. Published 2025-05-14.
How severe is CVE-2025-3875?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-3875 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.