SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2025-3523

This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

MEDIUM 6.4EPSS 0.31%

Does this matter?

Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own.

Description

When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only the last link is shown when hovering over any attachment. Although the correct link is used on click, the misleading hover text could trick users into downloading content from untrusted sources. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

CVSS 3.1
6.4 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L
EPSS
0.31% probability · 24th percentile
CISA KEV
Not listed
Weakness
CWE-451
Affected
mozilla/thunderbird
Source
security@mozilla.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.