CVE-2025-3932: It was possible to craft an email that showed a tracking link as an attachment
Source GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 29 Oct 2026, 22:52 UTC
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.
Description
It was possible to craft an email that showed a tracking link as an attachment. If the user attempted to open the attachment, Thunderbird automatically accessed the link. The configuration to block remote content did not prevent that. Thunderbird has been fixed to no longer allow access to web pages listed in the X-Mozilla-External-Attachment-URL header of an email. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.
References
- nvd.nist.gov/vuln/detail/CVE-2025-3932 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=1960412 (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)