CVE-2025-3523

6.4 mediumEPSS 0.3%

Medium (6.4) in mozilla thunderbird. EPSS 0.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

6.4 medium

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 24% of CVEs (scores of 2026-10-31)
CWE: CWE-451
Published: 2025-04-15
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1958385
https://www.mozilla.org/security/advisories/mfsa2025-26/
https://www.mozilla.org/security/advisories/mfsa2025-27/

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