6.4
Medium
CVE-2025-3523 When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only…
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Thunderbird 137.0 | earliest → < 137.0.2 | 137.0.2 |
| Thunderbird 128.9 | earliest → < 128.9.2 | 128.9.2 |
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