CVE-2025-5986

MEDIUM EPSS 36.9%
Published Jun 11, 20251y ago · Modified Jun 17, 20262w ago
6.5 CVSS 3.1
Medium
Find Similar
Published Jun 11, 2025 1y ago
Last Modified Jun 17, 2026 2w ago

Description

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 was fixed in Thunderbird 128.11.1 and Thunderbird 139.0.2.

CVSS Details

Base Score
6.5
Exploitability
2.8
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
36.9% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-451

Affected Products 2

VendorProductVersionRange
mozillathunderbird* <128.11.1
mozillathunderbird*≥135.0  –  <139.0.2

References 4

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/buglist.cgi?bug_id=1958580%2C1968012
    Broken Link
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html
  • mozilla.org https://www.mozilla.org/security/advisories/mfsa2025-49/
    Vendor Advisory
  • mozilla.org https://www.mozilla.org/security/advisories/mfsa2025-50/
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.