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.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1964767
• https://www.mozilla.org/security/advisories/mfsa2025-56/
• https://www.mozilla.org/security/advisories/mfsa2025-59/
• https://www.mozilla.org/security/advisories/mfsa2025-61/
• https://www.mozilla.org/security/advisories/mfsa2025-63/