CVE-2025-3877 Affecting thunderbird package, versions <1:128.10.1esr-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.03% (9th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-THUNDERBIRD-10168023
  • published15 May 2025
  • disclosed14 May 2025

Introduced: 14 May 2025

NewCVE-2025-3877  (opens in a new tab)

How to fix?

Upgrade Debian:unstable thunderbird to version 1:128.10.1esr-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream thunderbird package and not the thunderbird package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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 < 128.10.1 and Thunderbird < 138.0.1.

CVSS Base Scores

version 3.1