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 affects Firefox < 141, Firefox ESR < 140.1, Thunderbird < 141, and Thunderbird < 140.1.

References

https://www.mozilla.org/security/advisories/mfsa2025-63/

https://www.mozilla.org/security/advisories/mfsa2025-61/

https://www.mozilla.org/security/advisories/mfsa2025-59/

https://www.mozilla.org/security/advisories/mfsa2025-56/

https://bugzilla.mozilla.org/show_bug.cgi?id=1964767

Details

Source: Mitre, NVD

Published: 2025-07-22

Updated: 2025-07-23

Risk Information

CVSS v2

Base Score: 9.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 9.1

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Severity: Critical

EPSS

EPSS: 0.00018