by Kastro
Paper/Archive/CVE-2025-8037

CVE-2025-8037

Mozilla Firefox — Nameless cookies shadow secure cookies

EPSS 0.3%CVSS 9.1
critical.is priorityof 100
31
CVSS 9.1 (ADP)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 18.8.188 × 203.8No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
Firefoxsee advisory140.1CNA
Thunderbirdsee advisory140.1CNA

Scores by source

CISA ADP9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refbugzilla.mozilla.org/show_bug.cgi?id=1964767refmozilla.org/security/advisories/mfsa2025-56refmozilla.org/security/advisories/mfsa2025-59refmozilla.org/security/advisories/mfsa2025-61refmozilla.org/security/advisories/mfsa2025-63