CVE-2026-84138
Medium
Description
Denial-of-service in the PDF Viewer component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.
SeverityMedium
CVSS6.5
Exploit probability—
Product
Mozilla Firefox
PublishedSep 1, 2026
First seenSep 1, 2026
Weakness typeCWE-400Uncontrolled resource consumption
How to fix
Update
- mozilla firefox155.0.0 or later
- mozilla thunderbird155.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 155.0.0 | 155.0.0 |
| mozilla thunderbird | v < 155.0 | 155.0 |
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