cvedb.io
CVE-2025-5986
MEDIUM · CVSS 6.5
EPSS exploitation probability: 0%
Published 2025-06-11T12:15:29.183 · Last modified 2026-06-17T09:49:09.570

Summary

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.

Affected products

mozilla — thunderbird

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.