9.1
Critical
CVE-2025-8037 Setting a nameless cookie with an equals sign in the value shadowed other cookies
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Firefox 141 | earliest → < 141 | 141 |
| Firefox 140.1 | earliest → < 140.1 | 140.1 |
| Firefox ESR 140.1 | earliest → < 140.1 | 140.1 |
| Thunderbird 141 | earliest → < 141 | 141 |
| Thunderbird 140.1 | earliest → < 140.1 | 140.1 |