CVE-2025-3875: case the server · Thunderbird Parses Addresses
Source GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 138.0.1 : patch affected systems soon.
Data as of 30 Oct 2026, 01:41 UTC
- Patch
- Available – fixed in 138.0.1, 128.10.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 14 May 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
AI-suggested
This vulnerability is fixed in Thunderbird versions 128.10.1 and 138.0.1. Users and administrators should upgrade to at least these versions to remediate the issue. No additional mitigations are required once updated. The vendor advisory confirms the fix is available and recommends applying the official updates.
Description
Thunderbird versions prior to 128.10.1 and 138.0.1 contain a vulnerability where the email client parses the From header improperly, allowing sender spoofing if the mail server permits invalid From addresses. Specifically, malformed From headers with multiple addresses can cause Thunderbird to display a spoofed sender address. This vulnerability has been fixed in Thunderbird 128.10.1 and 138.0.1.
References
- nvd.nist.gov/vuln/detail/CVE-2025-3875 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=1950629 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/05/msg00022.html (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-34 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-35 (opens in a new tab)