VulnerabilityModified

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.

HIGH 7.5EPSS 0.38%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.38%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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: 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS: 0.38% probability · 31th percentile
CISA KEV: Not listed
Weakness: CWE-290
Affected: mozilla/thunderbird
Source: security@mozilla.org

References

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

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.