CVE-2025-8037
Critical
Description
Setting a nameless cookie with an equals sign in the value shadowed other cookies. Even if the nameless cookie was set over HTTP and the shadowed cookie included the `Secure` attribute. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.
SeverityCritical
CVSS9.1
Exploit probability—
Product
Mozilla Firefox
PublishedJul 22, 2025
First seenJul 22, 2025
Weakness typeCWE-614CWE-614
How to fix
Update
- mozilla firefox140.1, 141.0 or later
- mozilla thunderbird140.1, 141.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 140.1, v < 141.0 | 140.1, 141.0 |
| mozilla thunderbird | v < 140.1, v < 141.0 | 140.1, 141.0 |
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