Critical · published July 23, 2025
🔥 A nameless cookie with an equals sign can totally overshadow essential cookies, even if those cookies have the `Secure` attribute! Think of it like a sneaky restaurant that serves a mystery dish without a name, completely covering up the menu items you actually wanted. You order a delicious steak, but the mystery dish takes the spotlight, leaving you with something you didn't even ask for! This vulnerability can lead to unexpected behaviors, allowing a rogue cookie to override important security settings. An attacker could potentially gain access to sensitive information by manipulating cookies that should have been secured. This could be absolutely devastating for users relying on secure sessions!
Think of it like a sneaky restaurant that serves a mystery dish without a name, completely covering up the menu items you actually wanted. You order a delicious steak, but the mystery dish takes the spotlight, leaving you with something you didn't even ask for! The flaw arises when a nameless cookie containing an equals sign is set, causing it to shadow other cookies even those marked with the `Secure` attribute. This undermines cookie isolation and can lead to unintended consequences during web interactions.
This vulnerability can lead to unexpected behaviors, allowing a rogue cookie to override important security settings. An attacker could potentially gain access to sensitive information by manipulating cookies that should have been secured. This could be absolutely devastating for users relying on secure sessions! Update Firefox to version 141 or newer, and Thunderbird to version 141 or newer as well, to patch this critical vulnerability. Additionally, review cookie-setting practices in your application to ensure proper naming and security attributes are enforced. This is fixable! Patch those browsers and you'll be right on track to keep your web experience secure! 🛡️
| Product | Versions | Fixed in |
|---|---|---|
| mozilla/firefox | < 140.1 | 140.1 |
| mozilla/firefox | < 141.0 | 141.0 |
| mozilla/thunderbird | < 140.1 | 140.1 |
| mozilla/thunderbird | < 141.0 | 141.0 |