EUVD-2025-18099
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Lifecycle Timeline
4Description
A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data (e.g. using /dev/urandom on Linux) or to leak Windows credentials via SMB links when the email is viewed in HTML mode. While user interaction is required to download the .pdf file, visual obfuscation can conceal the download trigger. Viewing the email in HTML mode is enough to load external content. This vulnerability affects Thunderbird < 128.11.1 and Thunderbird < 139.0.2.
Analysis
A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data (e.g. using /dev/urandom on Linux) or to leak Windows credentials via SMB links when the email is viewed in HTML mode. While user interaction is required to download the .pdf file, visual obfuscation can conceal the download trigger. Viewing the email in HTML mode is enough to load external content. This vulnerability affects Thunderbird < 128.11.1 and Thunderbird < 139.0.2.
Technical Context
This vulnerability is classified as User Interface (UI) Misrepresentation of Critical Information (CWE-451).
Affected Products
Affected products: Mozilla Thunderbird
Remediation
Monitor vendor advisories for patches. Apply mitigations such as network segmentation, access restrictions, and monitoring.
Priority Score
Vendor Status
Ubuntu
Priority: Medium| Release | Status | Version |
|---|---|---|
| oracular | ignored | end of life, was needs-triage |
| noble | not-affected | code not present |
| plucky | not-affected | code not present |
| upstream | released | 128.11.1 |
| jammy | released | 1:128.12.0+build1-0ubuntu0.22.04.1 |
| focal | DNE | - |
Debian
| Release | Status | Fixed Version | Urgency |
|---|---|---|---|
| bullseye | fixed | 1:128.12.0esr-1~deb11u1 | - |
| bullseye (security) | fixed | 1:140.8.0esr-1~deb11u1 | - |
| bookworm | fixed | 1:128.12.0esr-1~deb12u1 | - |
| bookworm (security) | fixed | 1:140.8.0esr-1~deb12u1 | - |
| trixie (security), trixie | fixed | 1:140.8.0esr-1~deb13u1 | - |
| forky, sid | fixed | 1:140.8.0esr-1 | - |
| (unstable) | fixed | 1:128.12.0esr-1 | - |
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External POC / Exploit Code
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