How severe is CVE-2025-3875?

CVE-2025-3875 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-3875 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-3875?

CVE-2025-3875 affects Mozilla Thunderbird. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-3875?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-3875 have an EU (EUVD) identifier?

Yes. CVE-2025-3875 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-14938.

When was CVE-2025-3875 published?

CVE-2025-3875 was published on 2025-05-14 and last updated on 2026-06-17.

CVE-2025-3875

CVE-2025-3875 is a high-severity vulnerability in Mozilla Thunderbird with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-290.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-14938
Weakness: CWE-290
Affected product: Mozilla Thunderbird
Published: 2025-05-14
Last modified: 2026-06-17

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 [email protected] as the actual address. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.

Frequently asked questions

What is 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 [email protected] as the actual address. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.
How severe is CVE-2025-3875?: CVE-2025-3875 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-3875 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-3875?: CVE-2025-3875 affects Mozilla Thunderbird. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-3875?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-3875 have an EU (EUVD) identifier?: Yes. CVE-2025-3875 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-14938.
When was CVE-2025-3875 published?: CVE-2025-3875 was published on 2025-05-14 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

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