Critical severity · published Jul 22, 2025
CVE-2025-8037
Nameless cookies shadow secure cookies
9.1
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 19% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 140.1; before 141.0 · source: NVD
TH
Thunderbird · Mozilla
before 140.1; before 141.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-8037
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-8037
Permissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=1964767
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-56/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-59/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-61/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-63/
More from Firefox
10.0
CVE-2019-11708
Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability
9.8
CVE-2024-9680
Mozilla Firefox Use-After-Free Vulnerability
9.8
CVE-2010-3765
Mozilla Multiple Products Remote Code Execution Vulnerability
9.6
CVE-2022-26486
Mozilla Firefox Use-After-Free Vulnerability
8.8
CVE-2023-5217
Google Chromium libvpx Heap Buffer Overflow Vulnerability